Patent Application
20220412950
The invention relates to a method for measuring a sample, in which
In addition, the invention also relates to a measuring device, a computer program, computer program-product, as well as a test-device series, a data structure and data structure record, and a method for calibrating a test-device batch.
In sandwich assays, a sample containing the molecule being examined, i.e. the analyte, forms a bridge with a binder molecule (generally an antibody) in place on/fixed to the test base and with a stamped binder molecule (which is generally also an antibody) mixed with the sample. Any known stamp whatever, which can be measured (radioactive, coloured, fluorescent, magnetic, etc. stamps) can be used as the stamp.
Lateral-flow assays are one example of a sandwich assay. In lateral-flow assays the area, on which the stationary binder molecule is, is called the test line or corresponding area.
In addition to the test line, in lateral flow assays there is typically also a so-called control line or corresponding area. It is intended to produce a signal also when there is no, or insufficient analyte in the sample being analysed. The control line tells that the test is “in order” and the result is reliable. One can also refer generally to the test's usability.
The control line can be dependent on, or independent of the test line. A dependent control line is implemented in such a way that stamped binder molecules that have passed over the test line bind to it. The control line's signal/intensity, more generally the measurement result, is inversely dependent on the test line's signal. In other words, the more stamp that has bound to the test line, the less is left to bind to the control line.
An independent control line's signal does not, in turn, depend (at least specifically) on the test line's intensity. It can be implemented, for example, by using a second stamped binder molecule, which does not bind to either the test line or the analyte. A dependent control line is always located after the test line. An independent control line can, in principle, be located anywhere, even though, for example to be sure, it is generally located after the test line.
The Hook effect, i.e. the prozone phenomenon, is a phenomenon that influences in all so-called sandwich-type assays. One problem relating to known assays is, for example, that the Hook effect limits the test's dynamic operational concentration zone. Another problem is that, in addition, due to the Hook effect, very high concentrations of the analyte give a wrong result. Thus the Hook effect too can said to affect a test's usability. In addition, also the control and test line and their measurement leads to demands on the test device and also the measuring device.
Tests demanding a control line are additionally limited by the fact that they are unsuitable for use with so-called multiplexing. A multiplexing test means a test in which, for example, instead of one test line there are several, for example 5 test lines. All methods that are in any way based on a control line are unsuitable for use with such tests, as in practice each test line cannot have its own control line.
The present invention is intended to create a method, a measuring device, a computer-program product, a computer program, and a test-device series for measuring a sample. In addition, the invention is intended to create a data structure and data structure record, and further also a method for calibrating a test-device batch. Thus, the invention does not relate solely to the measurement of an unknown sample and the related equipment, but it also relates to the calibration of a measurement and test-device batch and the related equipment. The characteristic features of the various objects of the invention are stated in the accompanying Claims.
In the case of an unknown sample, i.e. one that is to be analysed, i.e. measured, the invention is based on calibration data being arranged for the measuring device and a set of criteria relating to one or more calibration functions being formed from it, which can be used to measure one or more detection areas of the test device's indicator part in connection with the development of the sample's measurement, i.e. before, for example, an end point set for the test device's measurement procedure, which can be set for the measuring device. In other words, the sample's measurement can be said to be being performed, one or more times, already when the development of the sample is in progress in the test device. On the basis of the measurement performed in this way, the usability of the sample's measurement can be determined. Based on the determination of the measurement's usability, it is also possible to control the progression of the sample's measurement on the measuring device and/or form information concerning the sample's measurement. Both of these can also take place in connection with the development of the sample's measurement, i.e. once again before the end point of the measurement procedure of the test device possibly set for the measuring device.
In the calibration method according to the invention, the signal given by the test device, i.e. the measurement variable using several different concentrations as a function of time, is in turn measured. Thus, the development functions of the concentrations are obtained. As the test develops on the test device, the measured measurement variable increases at a certain speed as time progresses. On the basis of the development functions obtained, the so-called calibration functions (standard curves) can be defined at different moments in time. The formed calibration functions with the sets of criteria related to them and defined in a set manner can be utilized in the measurement of an unknown sample by the measuring device.
The set of criteria can include at least one criterion value formed on the basis of the calibration function and related to it, together with conditions, on the basis of which the usability of the sample's measurement is defined in connection with the progression of the sample's measurement by the measuring device. In addition, if the sample's measurement is shown to be usable at the moment in time defined by the relevant calibration, on its basis the progression of the sample's measurement can be controlled and/or information can be formed concerning the sample's measurement.
If there is one criterion value with conditions, then, for example, two domains can be defined from the calibration function. If there are two (or more) criterion values with conditions, then, for example, three or more domains can be defined from the calibration function. In addition to the usability definition to be performed, the progression of the measurement can, owing to the invention, be controlled in different ways when the measurement variable is in different domains of the calibration function.
In some of the calibration function's domains, such as, for example, in the domain defined by the criterion values between them, the measurement of the sample is performed, forming and reporting, for example, its numerical analysis result. In some of the calibration function's domains, such as, for example, the area of the calibration function below the domain between the criterion values, the sample's measurement can be continued from the moment in time defined by the relevant calibration to the next moment in time defined by the calibration, which in turn corresponds again to its own calibration function. There, at the next moment in time, an examination like that above can be performed, or else the measurement can be directly performed, and a numerical analysis result of the sample formed and reported. Thus, the invention offers many different possibilities for measuring a sample, i.e. for determining its usability, and also for controlling the measurement itself.
In other words, when the calibration data, such as, for example, parameters of the calibration functions are included to a test-device batch's factory calibration, the quantitative result of a test, for example, at high sample concentrations can be reported already earlier and/or at low sample concentrations later than would otherwise be the case, on the basis of the formed sets of criteria. Due to this, compared for example to the test being measured only once, such as, for example, at the end point of the test device's measurement procedure defined and set by the measuring device, at which the reading of a test device is typically performed according to the prior art, one or more of the following exemplary advantages are gained using the invention:
1) The Hook effect can be recognized and erroneous results prevented,
2) The test's dynamic area expands upwards without the resolution suffering, and/or,
3) The test's dynamic area expands downwards without the resolution suffering.
According to some examples of embodiments, the invention can also be characterized in that
The method according to the invention functions with both qualitative tests (on a scale of +/− or negative, positive, highly positive) and also quantitative, (the result of which is expressed, for example, in concentration units (for example 250 mg/l)). As a test permitting a quantitative implementation, the resolution of the test is very good. In it, the result is reported as a reading value. In calibration, the result can also be reported as “result”±deviation, in which the deviation depicts the resolution.
Owing to the invention, a qualitative or quantitative result can be given already at an early stage, long before the end point set for the test's measurement, but however, before the Hook effect can influence the result. Thus, owing to the invention, the sample's speed of development in one or more detection areas of the test device's indicator part no longer affects the measurement result. In addition, the operator can be notified already at an early stage if the Hook effect influences the result.
In addition, the invention's advantages are also that the invention functions in all cases (all sandwich assays—not only lateral flow, all forms of the control line—not only dependent, but also independent, and entirely without a control line). Thus, the test can be implemented by simply reading the test line, i.e. more generally, the detection area, in the case of its method, the test device and also its measuring device. For its part, this simplifies the actual measuring device. Owing to the invention it does not require a measuring part to measure the control area. A corresponding advantage is also realized in test devices. They can, if desired, be implemented without a control part. In addition, the invention does not restrict its stamp to any particular test form.
By defining functionality according to the invention beforehand already in factory calibration, the method is, compared to most other ways, considerably faster than making the definition only once a test is being run using the measuring device. Thus, the invention also simplifies and thus facilitates implementing a test in an actual test situation. It does not include several stages complicating the test, for example, in the form of calibration. These make the test laborious and thus also time-consuming. Owing to the invention there is no need to run several samples on the measuring device before measuring an actual unknown sample. It is particularly challenging to perform calibration runs in field measurements, i.e. outside the laboratory. The same is also true, for example, of testing performed in small clinics.
In the following, the invention, which is not restricted to the embodiments described in the following, is described in greater detail with reference to the accompanying figures, in which
The invention is described first in the case of the calibration of the test and then in the performance of the actual test itself, i.e. for example, in the case of the measurement of a sample 19 with an unknown concentration, using the test device 10′ (
The changing parameters relating to the test strips 10/reagents (test chemistry 26) arranged in the test strips 10, which require calibration of the relevant test-device batch 29 for their different manufacturing batches, are, for example, that the speed of progression of the sample and/or the reaction speed of the analyte 30 being examined in the sample 19 with the reagents 26, or in the speed of development of the sample 19, can vary between different test-strip batches.
As stage 1703, a group of samples with a known concentration C0, C1, C2, . . . i.e. in this case the calibration samples S0, S1, S2, . . . , are arranged for the group 49 of test devices 10′ selected from the test-device batch 29, and equipped with an indicator part 20 for measuring one or more analytes 30 from the sample, i.e. from the calibration samples S0, S1, S2, . . . . In the case according to the described embodiment, the calibration sample S0, S1, S2, . . . is put on the sample pads 43 of the test strips 10 (
Further, as stage 1703, the samples are measured, i.e. the calibration samples S0, S1, . . . , Sn using the measuring device 11 from one or more detection areas 21 arranged on the test device's 10′ indicator part 20 and equipped with test chemistry 26 for the analysis of the sample S0, S1, S2, . . . In the measurement, the relevant detection area 21 of the test strip 10, i.e. in the example's case the test line 21′, is read, for example, at a specific set moment in time t1, t2, t3, . . . . Alternatively, i.e. instead of the point-like reading moments in time, the measurement signal formed from the reading of the test line 21′, i.e. the development of the measurement variable 23, can also be monitored continuously, or at some preset (short) intervals, which also give results at the relevant moments in time t1, t2, t3, . . . .
The reading interval can be dynamic, i.e. not necessarily constant, instead it can also change as time progresses. In other words, in any case, the measurement for each calibration sample S1, S2, . . . , Sn is made at several different moments in time. These moments in time, t1, t2, . . . , tn, thus form a time series, i.e. the question is of a time-series measurement, measured on at least one test strip 10 for the relevant one calibration sample S1. As the calibration sample S1 progresses on the test strip 10, the situation at the test line 21′ (the read measurement signal 23) changes as a function of time. Thus, at each moment in time t1, t2, . . . , tn, measurement signals M1, M2, . . . , Mn deviating from each other are obtained.
It is recorded at each moment in time t1, t2, . . . , tn belonging to the time series intended to be formed. It is characteristic for the measurement signal M1, M2, . . . that it increases as time progresses, because more stamped analyte collects on the test strip's 10 test line 21′ as time progresses. I.e., in other words, the measurement can be said to be increasing in measurement variable 23 i.e. as measurement signal 23. The vertical columns of
At high concentrations, the measurement signal 23 as a function of time stops rising and can even drop, due to the aforesaid Hook effect. In addition, even smaller concentrations can reach the same signal level as time progresses. Thus, as time progresses the signals of samples with a lower concentration also rise to become greater, thus corresponding to the signal given by a higher concentration, especially in a situation in which the Hook effect acts. As a result of this, the signals of samples with a lower concentration can mix with the signals of samples with a higher concentration, so that a sample's real concentration can no longer be determined, if measurement continues for too long.
The same measurement series can be repeated using several test strips 10 for this sample S1 with a single concentration C1. From the measurement signals of these measurement series (for example, of five parallel measurements) a mean value can then be formed at each moment in time t1, t2, . . . , tn, which then form a time series for the relevant concentration C1. In addition, in an as such known manner, the measurement can also be used to obtain data on the test strips' 10 deviation, while the quality of the test strips 10 can also be evaluated.
At different moments in time t1, t2, . . . , tn of the measurement, of the measurement signal (M1, M2, M3, . . . )—concentration C1 point pairs obtained by using the relevant calibration sample S1 (i.e. the measurement signals') mean values, if several measurements have been made using a single concentrations' C1 sample S1 ((M1, C1), (M2, C1), (M3, C1), . . . ), corresponding response curves can be formed. A specific response curve can be formed for each moment in time t1, t2, . . . , tn of the time series. Because the sample's Si1 concentration C1 is known in each response curve of different moment in time t1, t2, . . . , tn belonging to the time series, the measurements can be represented as a point pairs of measurement signal Mx (Y-axis)—concentration Cx (X-axis).
Time-series measurements (
Thus, concerning the aforementioned stages, one can speak of the formation of response curves using measurements performed at different points in time on different concentrations. In other words, in connection with the development of the measurement of each sample, at least some of the calibration samples S0, S1, . . . , Sn are measured on the detection area 21, to form development data 38.1 for the calibration sample's S0, S1, S2, . . . various concentrations C0, C1, C2, . . . . Based on the measurements, development curves corresponding to different concentrations can be formed.
The problematiques relating to measurement can also be explained with the aid of
c show, for example, data corresponding to two different points in time t1 (1.13 min) and t2 (5.08 min), and the corresponding response curves formed from them. Again it can be seen from these that in the longer measurement lasting to point in time t2 the measurement signal 23 at the highest concentration (3486 mg/l) of sample Sn is lower than the measurement signal of the sample Sn-1 (1743 mg/l) with the preceding concentration.
As stage 1705, calibration data 25.1 is formed on the basis of the development data 38.1 for at least one moment in time t1, t2 in connection with the development of sample's 19 measurement, to form a calibration function 32.1, 32.2 for the relevant measurement at at least one moment in time t1, t2. In other words, calibration functions 32.1, 32.2 are formed on the basis of the development data for different moments in time. This can be done, for example, in such a way that a function adaptation is made for the point pairs formed on the basis of the measurements performed above in the response curves at different moments in time t1, t2, t3, . . . . I.e. in the response curve of moment in time t1 an adaptation is made for the point pairs (M1, C0; M1, C1; M1, C2; M1, C3; M1, C4; and M1, C5), in the response curve of moment in time t2 for the point pairs (M2, C0; M2, C1; M2, C2; M2, C3; M2, C4 ja M2, C5), etc. to form corresponding calibration curves to each response curve corresponding to each moment in time t1, t2, t3, . . . of each time series. Even more generally, one can speak of the formation from the calibration curves of a function dependent on the development time. Hill's function is an example of this connection. Instead of the function adaptation, a time point calibration curve of one or more points in time can also be used, which can also be understood in this context as a calibration function. In addition, one or more of the calibration functions 32.1, 32.2 formed, the derivative of which is positive, is selected and recorded. The calibration function's 32.1, 32.2 derivative can be said to be positive, if its curve rises.
Further, each test-device manufacturer can, for example, define its own resolution criteria for its own products, entirely independently. Here, for example, the deviation (SD—standard deviation) can be calculated at the relevant moment in time for the parallel measurements of each sample and examine (e.g. visually or by calculating approximations) or by setting directly in the function the resolution at any point—i.e. the smallest step in the rise in concentration that can be reliably observed, taking the tests' deviation into account. Typically the criterion used is deviation (SD) or its multiple, for example 3×SD, which is already a very tight criterion. Alternatively, the share of deviation of the signal, i.e. the so-called CV (coefficient of variation) can also be calculated. This expresses the variation as a percentage of the signal. To give one example, the target can be, for example, <10% CV over the whole quantification range.
The calibration curve (or part of it) can also be, for example, a straight line, with a set kind of slope. Instead of straight line, to the point group can, using a calculation program (e.g. MS Excel) also fit some other kind of curve, so that straight line is not the only possibility. One or more parts formed from the calibration curve is, however, continuously rising with sufficient steepness (angle coefficient) for it to have an acceptable resolution and, in addition, the correspondence of the measurement signal—concentration should be continuous. In other words, the relevant part of the curve should indicate an increasing measurement signal, and thus also, as a result, an increasing concentration. In other words, the measurement signal should (in resolution clearly) increase as a function of concentration C at the relevant selected moment in time t1, t2, t3, . . . . This condition should be realized in each calibration curve 32.1, 32.2 selected to the calibration 25 of the measuring device 11. Thus, this operation too (adaptation and search for curve areas meeting the criteria) is done at several moments in time t1, t2, t3, . . . , of which one or more suitable moments in time are then selected for the calibration 25 formed for the measurement of an unknown sample 19.
As stage 1706 of
As the criterion values H, L linked to each calibration functions 32.1, 32.2 are defined at least one of the following: at least one measurement area's upper limit H or data corresponding to it, or at least one measurement area's upper limit H and lower limit L or data corresponding to these. The criterion values H, L are recorded, for example, with the calibration data 25.1, i.e., for example, with the calibration parameters. On the basis of the calibration parameters, i.e. the calibration data 25.1, calibration curves 32.1, 32.2 can be formed on the measuring device 11, in connection with which the criterion values H, L, belonging to the set of criteria Kt1, Kt2, are applied. The upper and lower limits H, L define the usable measurement area of the calibration function 32.1, 32.2, i.e. now the usable measurement area's upper limit H and the usable measurement area's lower limit L.
As stage 1706.2, in
If the measurement variable 23 measured from the sample 19 measured at the relevant moment in time t1 is less than the set criterion value, which is the measurement area's upper limit H, the sample's 19 measurement is categorized as usable, at least at this moment in time t1 defined by the relevant calibration 25, when the relevant measurement variable 23 was defined from the relevant sample 19 being measured. This is noted as stage 1706.4. In other words, here from the selected calibration function 32.1, 32.2 one or more concentration ranges (Lv, L), [L, H] are defined, by which a measurement, performed before the end point of the measuring procedure of the test device 10′ set for the measuring device 11, is usable at the concentrations of the sample 19 defined by the range in question.
As stage 1706.5, the measuring device 11 is set to define whether there is, in the calibration 25 arranged for it, yet another criterion value for the same relevant moment in time t1. In the embodiment according to the example, it is now the measurement range's lower limit L in the calibration function 32.1 at the relevant moment in time t1. If this has not been set, as stage 1706.7, the measurement of the sample 19 is set to be continued to the following moment in time t2, defined in the calibration 25. If in stage 1706.5 it is found that it has been set, then move to stage 1706.6. There it is examined whether the measurement variable 23 measured from the sample at the relevant moment in time t1 is in the measurement range between the lower limit L and the upper limit H bound to the calibration function 32.1. If it is, as stage 1706.8, the analysis result 24 is set to be defined and reported.
On the other hand, if as stage 1706.6 it is found that the measured measurement variable 23 is not at the relevant moment in time t1 in the range between the criterion values, i.e. now between the upper limit H and the lower limit L of the usable measurement range of the calibration function 32.1, in other words that it is below the set lower limit L, then as stage 1706.7 the sample's 19 measurement is set to be continued at the following moment in time t2 defined by the calibration 25.
The same is done for each selected measurement moment in time t2 belonging to the calibration 25 and to the calibration functions 32.2 corresponding to them. In other words, for each moment in time t1, t2, t3, . . . a measurement signal's lower limit L (Lt1, Lt2, Lt3, . . .) and a measurement signal's (and thus also a concentration's) upper limit H (Ht1, Ht2, Ht3, . . .) is defined on the basis of the curve portions meeting the set criteria defined above. Again more generally, one or more sub-areas of the function 32.1, 32.2 fitted to the point group is defined in each point in time t1, t2, t3, . . . of the sample's 19 measurement defined in the calibration 25, the derivative of which is continuously positive and in addition in value with sufficient resolution in the aforementioned manner. These limits L, H act as usability criteria of the curves 32.1, 32.2 and thus also of the measurement in each calibration curve 32.1, 32.2, i.e., at each point in time t1, t2, t3, . . . of calibration 25 in the measurement of a test sample 19 with an unknown concentration, at different points in time of the measurement, of which some are in connection with the development of the sample's 19 measurement on the test device 10′. In other words, the upper and lower limits H, L tell of the concentration range of the sample being measured, by which the calibration curve 32.1 formed at the relevant moment in time t1 can be applied in the measurement at the relevant moment in time t1.
Thus, on the basis of the measurements, test-device batch's 29 calibration 25 (calibration data) can be said to be formed for the sample 19 to be analysed. Calibration data 25.1 concerning one or more detection areas 21 can be said to belong to the calibration 25. On the basis of the calibration data 25.1, such as, for example, the calibration curve 32.1 formed of that for at least one moment in time t1, is information 28 concerning the sample 25 with an unknown concentration, to be formed by a measuring device 11 equipped with calibration 25, such as, for example, a numerical analysis result 24 of the sample 19. In addition, the calibration 25 can be said to also include the aforementioned set of criteria Kt1, Kt2, the criterion values L, H (and the ranges defined by them ((Lv, L), [L, H], (H, Hv)) belonging to it, the categorization formed on their basis, and the measuring device's 11 operating instruction based on the categorization, being based on the measurement's usability data for controlling the progress of the sample's 19 measurement, and/or to form information 28 concerning the sample's 19 measurement.
As stage 1707, the calibration data 25.1 concerning the test-device batch 29 is recorded in a data structure 18 formed for calibration 25, for taking to the measuring device 11. In addition as stage 1707 the set of criteria Kt1, Kt2 belonging to the calibration 25, together with the criterion values L, H and a possible corresponding categorization of the measurement of the sample 19, together with operating instructions, are also recorded. The categorization with the operating instructions can also be included in the computer program 37′, i.e. for example in the measurement program 37, which is executed using the measuring device 11 during the performance of the measurement of the sample 19.
Thus, the invention also concerns a data structure 18 for the calibration of the measuring device 11.
In addition, the calibration 25 arranged in the data structure 18 also further includes a set of criteria Kt1, Kt2. The set of criteria Kt1, Kt2 is for defining the usability of the sample's 19 measurement at at least one moment in time t1. At least one of the moments in time t1 is in connection with the development of the sample's 19 measurement. In addition to the definition of usability, the set of criteria Kt1, Kt2 is also for controlling the progress of the sample 19′s measurement and/or for forming information 28 concerning the sample 19 at one or more moments in time t1, t2 corresponding to the relevant one or more calibration functions 32.1, 32.2. As described in the example above, the data structure 18 can have been formed in connection with the factory calibration of the test-device batch 29.
As stage 1708, a data-structure record 34 is formed by arranging a data-structure 18 to a data-carrier 39 to take the calibration to the measuring device 11.
As stage 1709, a test-device series 31 is formed of the test devices 10 of the test-device batch 29, and thus also of those that are the objects of the calibration process described above, and the data carrier 39 containing the calibration 25. This can be, for example, a group of twenty test strips 10 and a calibration card 34′. The test strips 10 can have, for example, a 12 or 18-month usability period.
Thus, the invention also relates to the actual test-device series 31, of which an example is shown in
The test-device series' 31 data structure 18 is, in turn, arranged on the data carrier 39 to take the calibration 25 concerning the test devices 10′ to the measuring device 11 to measure the sample 19 using the device 10′. The calibration 25 includes calibration data 25.1 concerning the test devices 10′. The calibration data 25.1 is for forming information 28 concerning the sample 19. In addition, calibration 25 includes the set of criteria Kt1, Kt2 already described above, together with the criterion values and the categories they define. In other words, the data structure 18′ is a data structure 18 according to the invention.
Similarly, using the data it can be determined using the aforementioned principle that the usability of a measurement performed (the deviation of the measurements meet the set criterion, being less than it), for example, at a moment of time t2 is in the concentration range 20-1000 mg/l. From the data and the curve too the influence of the Hook effect on the measurement can be clearly seen at concentrations of more than 1000 mg/l, especially at the final concentration (3486 mg/l) of the measurement series. In other words, once again the lower limit Lt2 of the usability of the measurement at the moment in time t2 (5.08 min) can be set as 20 mg/l and the upper limit Ht2 of the usability of the measurement at moment in time t2 as 1000 mg/l. These limits Lt2, Ht2 are applied later by the measuring device 11 in measuring a test sample with an unknown concentration with the relevant calibration curve at the relevant moment in time t2.
As stage 1800 of
Stage 1800 can be divided, for example, into two sub-stages 1800.1, 1800.2. As sub-stage 1800.1, calibration data 25.1 for forming one or more calibration functions 32.1, 32.2 on the measuring device 11 for the measurement of sample 19 is downloaded and stored, more generally, arranged, on the measuring device 11. At least one of the calibration data 25.1 and thus also of the calibration functions 32.1, 32.2 formed from them, concerns the moment in time t1 in connection with the development of the measurement of sample 19. The measurement variable 23 measured from the sample 19 by the measuring device 11 can then also be said to be rising in value at the relevant moment in time t1.
As sub-stage 1800.2 in turn, a set of criteria Kt1, Kt2 relating to one or more calibration functions 32.1, 32.2 is downloaded and stored, more generally, arranged, in the measuring device 11. The set of criteria Kt1, Kt2 is for the definition of the usability of the measurement of sample 19 in connection with the development of the measurement of the sample 19 by the measuring device 11, and in addition, the progress of the measurement of the sample 19 and thus also for controlling the operation of the measuring device 11 on the basis of the measurement of the sample 19.
Thus, stage 1800 can be said to be the input to the measuring device 11 of the selected calibration curves 32.1, 32.2 (or the corresponding data required to form them, i.e., for example, the calibration parameters) of the formed calibration curves 32.1, 32.2, together with their usability data and their related upper and possible lower limits H, L at different moments in time t1, t2, along with the corresponding operating instructions, which can also be part of the sets of criteria Kt1, Kt2. In other words, factory calibration formed beforehand for the test-device batch 29 is then set for the measuring device 11. Then, in the measurement of the sample 19, the measuring device 11 should use the test-device group 49′ formed from this relevant test-device batch 29, for which the calibration in question has been made in connection with the development of the measurement of the relevant sample 19, which it thus now concerns. In other words, the calibration 25 with the sets of criteria Kt1, Kt2 and calibration data 25.1 can be said to be arranged for the measuring device 11 in the form of the factory calibration of the manufacturing batch of test devices 10′.
With reference to
As stage 1802, the sample 19 to be analysed is measured by the measuring device 11 from one or more detection areas 21 arranged on the test device's 10′ indicator part 20 and equipped with test chemistry 26 for the analysis of the sample 19. Thus, the test device 10′, such as, for example, a test strip 10 is placed in the measuring device 11 and the measurement of the test device 10′ with the sample 19 is started. In the measurement, a measurement signal is formed from the test device 10′, i.e. now from one or more detection areas 21 of its indicator part 20. The measurement signal can also be called the measurement variable 23 or measurement result. Thus, it is, for example, an electrical primary variable, which the measuring device 11 forms from the test device 10′ in the measurement in connection with the performed measurement of the sample 19.
In stage 1802, the measuring device 11 is used to measure one or more detection areas 21, i.e. the sample 19 to be analysed, at the moment in time t1 in connection with the development of the sample's 19 measurement. The measurement of the sample 19 can be said to develop in the test device's 10′ detection area 21, because the measurement signal formed in the sample's 19 measurement, i.e. the measurement variable 23, changes as a function of time. Thus, every measurement moment of time, at which the sample 19 is measured to form a measurement result 23 from it and to analyse it, also requires its own calibration (curve), because the measurement signal increases, i.e. more generally changes, continuously as the sample's 19 measurement develops in the test device 10′. One can also say that the measurement is then performed at at least one moment in time t1, which is before the end point of the measurement of the test device 10′ typically preset on the measuring device 11. Measurement not until the measurement's end point of the test device 10′ set for the measuring device 11 is a known form of operation in known measurement methods for performing the measurement of a sample 19.
Thus, in stage 1802, one can say that the sample 19 is allowed to develop in the test device's 10′ indicator part 20, and now even more particularly, its detection area 21, when it is measured using the measuring device 11. Here the development of the sample 19 means, for example, in the case of a lateral-flow assay 10*, for example, to at least one or more of the following: the sample's 19 progression on the test strip 10, the sample's 19 reaction with the test chemistry 26 arranged on the test strip 10 and/or particularly the stamped sample's 19 accumulation in one or more detection areas 21 of the indicator part 20 for the reading of the test, i.e. the measurement of the measurement variable 23 taking place in the measuring device 11. From these, especially from the last of them it can also be said that the measurement variable 23 is measured in connection with the sample's 19 development at least at one moment in time t1, when the measurement variable 23 measured from the sample 19 has a value that is an increasing as function of time.
In stage 1802, the test line 21′ of the test strip 10 is measured at at least one moment in time t1 defined in the calibration 25 and brought to the measuring device 11. The moment in time t1 is defined from the time series measurement performed in connection with the calibration measurements of the test-device series 31 and from the calibration functions 32.1 formed on their basis. As already noted earlier in the method description of the calibration measurement, it is not necessarily possible to provide any generally applicable criterion for the sample's 19 measurement moment in time t1. However, it is generally possible to estimate, for example, the steepness of the rise of the measurement signal defined in the test-device series 31 calibration stage and the deviation of the measurement results 23 in calibration and on their basis to define one or more calibration functions 32.1, 32.2 and thus also the moment in time t1, t2,, that suits the measurement's performance in the way according to the invention.
On the other hand, though the measurement results' deviation would be great at the first moment in time t1 at which the measurement is performed, the samples 19 with already very high concentrations, for example, can nevertheless be identified at the relevant moment in time t1. This is especially so if, for example, the steepness of the calibration curve 32.1 is sufficient at the relevant moment in time t1. In the factory calibration of the test-device batch 29, the measurement's first moment in time t1 is set to be some specific moment in time, i.e. when using the product (a test strip 10 belonging to the relevant test-device batch 29), all the test-device's 10′ measurement moments in time, and the measurement results' upper and lower limits H, L, by which the measuring device's 11 operation and the progress of the measurement are defined, are known precisely beforehand in the measuring device 11, which then performs the sample's 19 measurement according to them.
The moment in time t1, when the first measurement is performed and on its basis the first measurement indication is also given to the end user of the measuring device 11, can be (even considerably) earlier than the measurement time defined and set for the measurement (for the test device 10′), i.e. the end point of the measurement procedure set for the test device 10′, at which the measurement result is formed and reported according to the prior art. One exemplary criterion for this preset measurement's end point can be, for example, that then the test strip 10 can be entirely wet with the sample 19.
As stage 1803, the usability of the sample's 19 measurement is defined on the basis of the measurement performed and of the calibration 25 of the test-device batch 29 arranged for the measuring device 11 and of the set of criteria. I.e., this too takes place in connection with the development of the sample's 19 measurement, at the moment in time t1 defined in test-device batch's 29 calibration. In other words, this too can be said to take place, at least once, before the end point of the test device's 10′ measurement procedure set for the measuring device 11.
On the basis of the definition of the measurement's usability, the progress of the sample's 19 measurement can be controlled on the measuring device 11. In addition, on the basis of the definition of the usability of the sample's 19 measurement, information 28 can also be formed concerning the sample 19 or even more generally, the sample's 19 measurement.
The definition of the measurement's usability and in addition the control of the progression of the measurement are based on the set of criteria Kt1 belonging to the calibration 25 and formed in connection with the development of the sample's 19 measurement at at least one moment in time t1. The set of criteria Kt1 in turn includes at least one criterion value H defined from the calibration function 32.1 corresponding to the relevant moment in time t1. On the basis of the criterion value H, the measurement to be performed on the sample 19 can be categorized at the relevant moment in time t1 into two categories A, BC. The categorization now relates to the usability of the measurement. The categorization is based on the value ranges ((Lv-L), [L-H] (H-Hv)) defined from the calibration function 32.1 on the basis of one or more criterion values H, L at the relevant moment in time t1, t2.
If, only one criterion value H, i.e. a criterion value H defining the upper limit of the usable measurement area of the calibration function 32.1, 32.2 is formed in calibration, then the value areas can be, for example, (Lv-H], (H-Hv). If, in turn, in calibration two criterion values H, L are formed at the relevant moment in time t1, i.e. the criterion value H defining the upper limit of the usability of the calibration function 32.1 and, in addition, the criterion value L defining the lower limit of the usability of the calibration function 32.1, the value ranges can be (Lv-L], [L-H], and (H-Hv). In both, Lv and Hv refer to the starting point and end point of the calibration function. On the basis of those value ranges (Lv-L], [L-H], and (H-Hv), the usability of the sample's 19 measurement is defined in connection with the development of the sample's 19, and/or the progress of the measurement in connection with the development of the sample's 19 measurement is controlled, at the stages described in greater detail in the following.
In stage 1803.1 shown in greater detail in
As stage 1803.2, the measuring device's 11 operator can be notified, as information 28 concerning the sample 19, that the test sample's 19 concentration exceeds the test's dynamic range and the measurement has been interrupted. In addition, the operator can be instructed, for example, to dilute the sample 19 and perform the measurement again. Thus, on the basis of the set of criteria Kt1, Kt2, and even more particularly of at least one criterion value H belonging to it, the sample's 19 measurement is rejected, if the measurement variable 23 formed using the measuring device 11 on the basis of the measurement of the detection area 21 exceeds the criterion value H belonging to the set of criteria Kt1 at the corresponding moment in time t1. In other words, the sample's 19 measurement result is then in connection with the development of the measurement of the sample 19 in at least one value range (H-Hv)) defined from the calibration function 32.1 on the basis of the criterion value H and on its basis the progress of the sample's 19 measurement is controlled in such a way that the sample's 19 measurement is interrupted.
If, on the other hand, it is shown in stage 1803.1 that at the relevant moment in time t1 defined by the calibration 25 the measurement signal 23 measured from the sample 19 in the detection area 21 is less than the upper limit H of the usable measurement area defined from the calibration curve 32.1 at the relevant moment in time t1, a move is made to stage 1804. In stage 1804, the sample's 19 measurement is continued, because as stage 1803.1 the sample's 19 measurement was found to be, at least at the relevant moment in time t1, still usable. Thus, the calibration 25 then includes the set of criteria Kt1 with the criterion value H, formed at least at one moment in time t1.
In other words, in the case according to the embodiment, the categorization A, BC made of the basis of the value ranges (Lv-H], (H-Hv) defined by at least one criterion value H belonging to the set of criteria Kt1, Kt2, concerning the usability of the sample's 19 measurement and/or the control of the progress of the measurement in connection with the development of the sample 19 defined at the moment in time t1, can comprise one or more of the following: at least one value range (H-Hv) of the measurement result 23 defined in stage 1803.1, by which the sample's 19 measurement is rejected (usability category A) and at least one value range (Lv-H] of the measurement result 23, on the basis of which the sample 19 is measured to define the analysis result 24 from the sample 19 as stage 1804 (as usability category BC). Thus, the categorization can be said to be based on the measurement result's 23 value ranges (Lv-L), [L-H], (H-Hv) defined from the calibration function 32.1, 32.2 on the basis of the criterion values L, H.
As stage 1804, the progress of the measurement is controlled and/or information 28 concerning the measurement of the sample 19 is formed on the basis of the usability of the measurement found in stage 1803.1. If the criterion values were only one at the relevant moment in time t1 in connection with the development of the sample's 19 measurement, i.e. the upper limit H already described in the aforementioned stage 1803.1, then the measurement result of the sample 19 has to be in the value range defined by the criterion value H of the set of criteria Kt1 in stage 1804.1, i.e. in the calibration function's 32.1 value range (Lv-H), which is thus now the value range of the calibration function 32.1 below the criterion value H. One then moves to stage 1804.4.
In stage 1804.2, the progress of the sample's 19 measurement is controlled in such a way that the sample's 19 measurement is continued to the next moment in time t2 defined by the calibration 25, as set in the diagram of
Instead of that, if there were at least two criterion values at the relevant moment in time t1, i.e. the already aforementioned upper limit H defined from the calibration function 32.1 at the relevant moment in time t1, and in addition to that the lower limit L defined from the calibration function 32.1 at the relevant moment in time t1, then in stage 1804.1 it is determined whether the sample's 19 measurement result is in the value range defined by the set of criteria Ktu i.e. now in the value range L-H of the calibration function 32.1 at the relevant measurement moment t1. It is characteristic of the one or more value ranges L-H defined by one or more criterion values L, H belonging to the set of criteria Kt1, Kt1, that in them the derivative of the calibration function 32.1 formed on the basis of the calibration data 25.1 is continuously positive. In addition, it is characteristic of the one or more value ranges L, H defined by the one or more criterion values L, H belonging to the set of criteria Kt1, Kt1, that the calibration function 32.1 formed on the basis of the calibration data 25.1 has sufficient resolution, taking the test devices' 10′ measured deviation into account. If the measurement variable 23, i.e. result, formed by the measuring device 11 on the basis of the measurement of the detection area 21 is in the value range [L-H] of one or more calibration functions 32.1 defined by the set of criteria Kt1 corresponding this relevant moment in time t1, more particularly its criterion value H, L, then too one progresses to stage 1804.2 already described above.
In stage 1804.2, the progress of the sample's 19 measurement is controlled in such a way that, of the basis of the set of criteria Kt1, Kt2, the sample's 19 measurement at the relevant moment in time t1 is accepted and as the next stage 1805 is formed and reported as information 28 concerning the sample 19, the sample's 19, for example, numerical analysis result 24.
Thus, if the measurement signal is between the lower limit L and the upper limit H, defined from the calibration function 32.1 at the relevant moment in time t1, the analysis result 24 is read from the calibration curve (
In the embodiment described of two criterion values H, L, if in stage 1804.1 it is found, on the basis of the measurement of the detection area 21, that the measurement variable 23, measured and formed by the measuring device 21, is less than the criterion value L defined from the calibration function 32.1 belonging to the set of criteria Kt1, i.e. it is thus in the calibration function's 32.1 value range (Lv-L) and not in the value range defined by the set of criteria Kt1, Kt2, i.e. [L-H], the measurement result is then below the criterion value L. Then, on the basis of the set of criteria, and even more particularly of the criterion values L, H belonging to it, one moves to stage 1804.4. According to it, the sample's 19 measurement is continued to the following moment in time t2 defined by the calibration 25. One then returns to stage 1802. Thus, the progress of the sample's 19 measurement and the operation of the measuring device 11 is once again controlled on the basis of the set of criteria Kt1, Kt2. The continuation of the measurement to the following time point t2 can also be notified to the measuring device's 11 operator. In other words, at this point too information 28 can be formed concerning the sample's 19 measurement.
In other words, if it is found in stages 1804.2 and 1804.3 that the measurement signal 23 is less than the lower limit L defined from the calibration curve 32.1 of the relevant moment in time t1, the measurement is allowed to continue, for example, to the end, or else to next one or more (now one) moments in time t2 defined in connection with the calibration, i.e., for example, at the 5-minute point. Thus, the second, or more generally the last measuring time can be, for example, the measuring time (the ‘end’/development point of the measurement) set as the end point of the test device 10′ in question. It can vary, for example, depending on the test. Of course there can be still more moments in time between the first measurement and the end point preset for the performance of the measurement, by which the measurement can be performed according to the principle of the invention.
Thus, in the case of the two criterion values H, L, the calibration 25 and the set of criteria Kt1, Kt2 belonging to it can have been formed for at least two moments in time t1, t2. At least one of the moments in time t1 is then in connection with the development of the sample's 19 measurement, i.e. before the end point set for the measuring procedure, defined from the calibration function 32.1 corresponding to the relevant moment in time t1. The corresponding categorization, i.e. the operational control of the measuring device 11 then comprises three categories A-C. These are the measurement's interruption (A) in the value area of the calibration function 32.1, 32.2 exceeding the criterion value H, the formation and reporting of the analysis result 24 from the sample 19 (B) in the value area of the calibration function 32.1-32.2 between the criterion values H and L, and the continuation to the next point in time of the measurement (C) in the value range of the calibration function 32.1, 32.2 that is less than the criterion value L.
Above, the usability data of the measurement and, in addition, also the analysis result were obtained according to the invention already when the development of the sample's 19 measurement was in progress. The same result would be obtained equally if one waited for the end point set for the test, i.e., for example, up to 5 min (t2), assuming that at the 5-min point (t2) the measurement signal is still between the lower and upper limits (L and H) of the calibration curve 32.2 formed for that moment in time t2. Thus, because the calibration curves 32.1, 32.2 defined for different moments in time t1, t2 can have dynamic, i.e. usability ranges differing from each other (at least partly) and thus also the criterion values L, H defining them, on the basis of which the progress of the measurement is controlled and/or information 28 concerning the sample's 19 measurement is formed can differ, this is not necessarily the case. Thus, by waiting until the end point set for the test (according to the prior art), a reliable measurement and analysis result may not be obtained at all for the sample 19 in question. Such a situation can, however, be avoided owing to the invention by performing the measurement as described above according to the invention when the test is still in the development stage and thus a reliable measurement and analysis result obtained from the relevant same sample 19. I.e., in other words, at at least one moment in time t1, t2 of the sample's 19 measurement is before the influence of the Hook effect on the sample's 19 measurement defined in connection with the test device's 10′ calibration.
As already stated above, as stage 1804 information 28 is formed on the basis of the measurement performed on the sample 19 and as stage 1805 the measuring device 11 reports the said information 28 concerning the sample 19 measured by the measuring device 11 and/or the progress of the measurement. As described above, the information 28 can be formed using calibration 25 concerning one or more detection areas 21, which is arranged for the test device 10′ and the sample 19 arranged to be analysed using it. The calibration 25 can be arranged for the measuring device 11, particularly if the information 28 too is formed and reported by it. In addition, the calibration 25 can be arranged for the measuring device 11 already beforehand, i.e. before the actual measurement of the unknown sample 19. Thus, the sample's 19 measurement is possible without requiring the operator to perform preparatory measures relating to the measurement to be performed. In addition, the information 28 can be said to be formed on the basis of the measurement result 23 and its formation, i.e. in connection with the measurement. The information 28 can be reported using the corresponding measuring device 11, by which the actual measurement of the sample 19 was performed. The information 28 can be, for example, the sample's 19 numerical analysis result 24.
As stage 1806, the test device's 10′ measurement procedure is terminated at the end point of the measurement of the test device 10′ set for the measuring device 11. It can be set for the measuring device 11, for example, along with the calibration 25 and is according to the invention described immediately above, i.e. dynamic, depending on the stage of development of the sample's 19 measurement the measurement's usability data is obtained and on its basis the sample's 19, for example, numerical analysis result 24 is formed.
As already explained above, in the invention it is possible to operate at even a single point in time t1 of the measurement and thus with the calibration curve 32.1 relating to it. This is particularly the case when the calibration curve's 32.1 dynamic range is sufficiently large, i.e. it covers both low and also high concentrations. According to an exemplary embodiment, a typical implementation can, however, be, for example, such that, for example, 2-4 calibration curves are used, such as, for example t1 (1.13 min) and t2 (5.08 min) points in time, and possibly also, for example, t3 (for example, at the 15-min point). In some special cases even more calibration curves can be used. This is particularly so if all the curves have different dynamic areas, or at least one that deviates from each other at some point, with which the deviation and test sensitivity (derivative's magnitude—large slope) is optimal in different curves and according to the sample's 19 concentration a suitable calibration curve 32.n is used at a suitable moment in time tn. The curves' usability can thus also be said to be concentration-dependent.
Thus, in short, the dynamic range of the test on the usability of the measurement is expanded, according to the invention, by performing the test at two or more different moments in time, and thus also the test's calibration for two or more different moments in time. The actual measurement of the test sample can then also be performed at a set moment of time defined by the calibration, and the test sample's concentration can be ascertained already before the test's development to its “end point”, if the measurement signal given by the sample 19 at the relevant measurement moment defined in the calibration is in the usability range (L-H) of the calibration curve 32.1 formed for the moment. In addition to the expanded dynamic range this also accelerates the giving of the test result and thus increases the user-friendliness of the measurement and measuring device to the patient and the measurement performer. Thus, the sample's 19 analysis result is formed and reported as information 28 at the first moment in time t1, t2,, of the sample's 19 measurement defined by the calibration 25, if the measurement variable 23 is in the value range [L, H] defined by the criterion values L, H of the set of criteria Kt1, Kt2.
In the context of the invention, the value interval [L, H] can be referred to as, for example, the quantification range. This refers to the range, in which the measurement result, such as, for example, a specific concentration, can by some set criterion be differentiated from the other measurement results, such as, for example, the concentrations (resolution). Other criteria defining the value interval can be, for example, customer specifications, the characteristic behaviour of a test-device batch 29, a product's/test's repeatability, deviation, resolution, etc. What is important, however, is that the dynamic ranges of the points in time t1, t2 used in the measurement are consecutive or partially overlapping. In other words, there are then no openings in the dynamic range of the calibration totality, which any calibration function 32.1, 32.2 used does not cover. In some cases, the dynamic range defined by the calibration could even be discontinuous, but this is not one of the invention preferred embodiments.
In some cases, as was already stated above, the lower limit L and the upper limit H of the calibration curve's usability area [L, H] can even be of equal magnitude. Such a case would be precisely such an application, in which the expanded dynamic range is not utilized, instead it is only reported to the operator that the sample's 19 concentration exceeds the dynamic range, i.e. that measurement with the relevant sample is not usable. For example, at the moment in time t1 a measurement can be made to test if the measurement result is >H. If it is, the measurement is not continued, instead it is reported that the measurement result exceeds the test's dynamic range. If the measurement result at time t1 is <L, (i.e. if L=H) a situation will not arise, in which a numerical result would never be given at time t1—then H, i.e. the upper limit can be “forced erroneously” to be the same as L. I.e., if it was wished to give a numerical result, L would not be the same as H, but by setting them to be the same, the desired behaviour of the measuring device 11 is obtained from the same algorithm without a need for a different algorithm for this special case, then the test is allowed to develop further and is measured again at the moment in time t2, when a function adaptation and L and H values made for this latter moment in time are applied. If the result is between L-H, the result/signal is placed in the function and the operator is given the result (in concentration units). L and H can be defined, for example, either as signal levels (for example, as bits) or as concentration units after placing in the function. In principle, they can be defined behind any kind of calculation, for example, for encryption, but what is important is that they are used to tell the measuring device 11, whether it can apply the calibration function 32.1, 32.2 to give a numerical analysis result 24 (i.e. to place the measurement signal in the calibration function).
Owing to the invention, the dynamic area of the test can differ at different points in time. Thus, by performing calibration and, as a result, also the measurement itself at several different points in time t1, t2, owing to the invention a wider measurement range is obtained for the test. In addition to that, and even though the test's dynamic range would be same at different points in time, using the method according to the invention it is nevertheless possible to further reduce the deviation due to the measurement and possibly detect deviations taking place in the test's development (above-mentioned Hook's phenomenon, a possibly too small amount of sample, flooding of the test base, etc.).
In addition to methods for forming calibration data for the measuring device 11 and for performing measurement using the measuring device 11, the invention also concerns a corresponding measuring device 11 and computer programs 37′. The devices, particularly the measuring device 11 and also the device that is used to calibrate the test, are configured to operate according to the methods. This is also implemented in the computer programs 37′.
On such can be the clock counter 36. For example, to the processor part 13 can be such embedded in. The measuring device 11 will then be without a separate special clock counter 36.
The reader part 16, which can also be called the measuring means, is equipped with at least one reader element 16.1. The reader part 16 is arranged in the reader element 16.1 to measure from the test device's 10′ indicator part 20 one or more detection areas 21 equipped with a test chemistry 26 for the sample's 19 analysis. There are numerous different ways to implement the reader element 16.1. According to one embodiment it can include an impulse part 33.1 and a response part 33.2. The impulse part 33.1 is used to send an excitation signal to the detection area 21, such as, for example, a light beam 46, which is read in turn by the response part 33.2, i.e. the detector. The impulse and response parts can also be one and the same unit, such as, for example, in measurement performed using a magnetic sensor 16′, which forms a magnetic field MF, from the change of which the measurement result is ascertained.
The test device's 10′ receiver part 35 is arranged in connection with the reader part 16. It is arranged to receive the test device 10′ in connection with the measuring device 11 for measuring the sample 19. Thus, the excitation effects and the response's reading take place in connection with the receiver part 35, in the influence area of which is at least one detection area 21 of the test device 10′, in connection with the sample's 19 measurement. The receiver part 35 appears outwards from the measuring device 11, for example, as a reception opening for the test strip 10.
Memory 14 is arranged in the measuring device 11 for calibration 25 concerning one or more detection areas 21 of the test device 10′. The data belonging to calibration 25 is in the memory 14, as are the measuring device's 11 operating system and the applications to be executed in it, such as, for example, the measurement program 37 according to the invention. Of these, at least the calibration 25, but possibly also the applications can be updated. The device's 11 memory 14 includes, in addition, reservations, for example, for measurement results, measurement parameters, and the control of the hardware. The measuring method used by the device 11, in addition to its factory installation, can thus be updated.
Of course a similar operation, i.e. the provision of the calibration parameters 25.1 and the related sets of criteria Kt1, Kt2 for the measuring device 11, can also be implemented in the form of an electric signal, for example, by downloading through a (partly wireless) data network, i.e. without any physical data storage means 34, 34′ particularly to be installed in the measuring device 11. There are then data-transmission means in the measuring device 11, (or, for example, in a computer connected to it) for downloading calibration data 25, for example, from an external server or similar. An example of this is, for instance can be said the test-device manufacturer's server, in which calibrations 25 are stored and can be downloaded test-device-batch specifically.
The processor part 13 is connected to the reader part 16 to form a measurement variable 23 from the sample 19 being analysed to be arranged in connection with the receiver part 35 arranged to the test device 10′. Information 28 on the sample 19 i.e. for example the sample's 19 analysis result 24, based on the measurement variable 23 is, in addition, arranged to be formed by the processor part 13, using the calibration 25, arranged for the sample 19 being analysed, concerning one or more detection areas 21 prearranged, for example, in the measuring device's 11 memory 14.
The clock counter 36 is for controlling the operation of the processor part 13, for performing the sample's 19 measurement. It can be used to determinate, for example, the termination time of the measuring procedure at the end point of the measurement of the test device 10′ set for the measuring device 11.
The output part 12.2 is for reporting information 28 relating to the measured sample 19.
The measuring device 11 can be connected to a computer or similar data-processing device, for example, through a data-transfer interface 17 arranged in it. In addition, there are user interface means 12 in the device 11. These now include input means (keyboard) 12.1 and output means (display) 12.2. In the measuring device 11 there is also a data-transfer interface 41 for taking the calibration parameters to the measuring device 11 using, for example, a card-form data carrier 39.
In the measuring device 11, the processor means 13 are arranged to control the operation of the measuring device 11 in such a way that by the reader part 16 is arranged to measure one or more detection areas 21 at a moment of time t1, t2 defined by the clock counter 36 in connection with the development of the sample's 19 measurement. At least one of the moments in time is before the preset end point of the test device's 10′ measurement. In addition, the processor means 13 are arranged to control the measurement device's 11 operation in such a way that, on the basis of the measurement performed by the reader part 16 and the calibration 25 arranged in the memory 14, the usability of the sample's 19 measurement in connection with the development of the sample's 19 measurement is defined, on the basis of which the progress of the measurement is arranged to be controlled and/or information 28 concerning the sample's 19 measurement is arranged to be formed. The processor means 13 are arranged in the measuring device 11 to perform the sub-stages of the method according to the invention.
The invention also relates to a computer-readable storage means 14′. It is arranged to store the program 37, which performed by the processor part 13 of the measurement device 11, which includes a reader part 16, receiver part 35, clock counter 36, and output part 12.2, achieve the measuring device 11 to operate, such as a measuring device 11 according to the invention. The storage means 14′ is, for example, the measuring device's 11 memory 14.
Yet another object of the invention is a computer program 37′. The computer program 37′ includes instructions, which achieve the measurement device 11 implement the method according to the invention, when the computer program 37′, more particularly the measuring program 37 is executed in the programmable measuring device 11.
The calibration measurements can be performed, for example, by a corresponding measuring device 11, by which the measurement itself (by the end user) takes place. Here the difference may be only in the software. In the calibration measurement the result can be, for example, an LSB value (the result of an AD converter, i.e. a linear of, for example, amount of the magnetic particles). Of course the same measurement procedure is also possible using, for example, an optical measurement methods, i.e. the invention is not restricted to the magnetic particles referred as an example. The adaptations and the formation of the calibration functions and limits L, H can take place on a computer using a suitable program.
In addition to the use of the invention eliminating the Hook effect, owing to it the upper end of concentrations can also be measured with a short development time t1 and with a longer development time t2 the lower end of concentrations can be more reliably measured. The lower and upper limits Lt1, Lt2 and Ht1, Ht2 in the previous example depict this well. In other words, with a short development time, for example, the deviation caused by the test strips 10 is taken into account, particularly at low concentrations. Thus, the low signals' low LSB values, and the deviation appearing in them, limits the range of usability of the calibration curves 32.1, 32.2 in the earlier moments of time of the measurement.
The deviation is caused, for example, by the test's manufacturing. It can be seen from the calibration measurements' mean value that the result of high concentrations remains hidden under lower concentrations.
When using the test according to the example, the deviation can in reality also be at the one-minute point, due to the test's manufacturing. Instead of deviation, one can speak, for example, of the total error, i.e. by how many precent the mean value deviates from that expected. To this is added the mean deviation using a suitable reliability range, i.e. +1.65*SD, i.e., for example at a 90-% reliability range. A specific acceptance criterion exists for this, i.e. it must be, for example, less than 26%. The actual mean deviation does not necessarily drop, but the results are nevertheless more valid if the mean value is closer to that expected. In any event, purely deviation (SD not even % CV) will not necessarily tell the truth, if the mean value is totally wrong.
In the title invention, in which only the test line 21 itself is important, the method is independent of how many reactions independent of each other take place in the test device 10′. Thus, the idea according to the title invention can equally also be applied in multiplexing tests, in which there can be several detection areas in the same test device 10′. Because a control area is not necessarily needed at all in the invention, this substantially simplifies both the test-device implementation and also the measuring device 11.
At several points in the present application reference is made by way of example to a test strip 10 or a corresponding group. More generally however, instead of a test strip 10 one can speak of a test environment or a test set-up. The test environment or set-up can also be called even more generally the test device 10. The reagents are placed on the test device 10′ in such a way that, when a test reaction occurs, the measurement signal increases as a function of time. Some, but not restrictive, examples of test devices 10′ can be said a lateral-flow assay 10* and an SPR (surface plasmon resonance) device. Or more generally, all sandwich-assay test devices 10″.
Referring to
The description of the test device's 10′ parts can be extended to the side of micro-fluidistics. Then the porous material characteristic of lateral-flow assays is replaced with microchannels. A porous material too contains these same microchannels, because it is porous—but micro-fluidistics generally refers to intentionally and manageably made channels. Of course, there is much that is manageable in the manufacturing process of a porous material too, but the channels are often random in shape and dimension, in addition to which there is a relatively wide deviation in their shapes and dimensions.
For example, the SPR (surface plasmon resonance) implementation can also work in a cuvette, i.e. the test device 10′ then also lacks a receiver part 43, a capillary flow 47, and also a collector part 44. The cuvette's bottom then corresponds to the test line, i.e. acts as the detection area.
Sandwich is a well-established name for a test type, in which two binding molecules are used, of which at least one bonds specifically to the molecule 30 being examined. The molecule being examined bonds between these two binding molecules. Often the one binder is immobilized, for example, as a test line 21′ on the cuvette's bottom or in the porous material and the other binder is free in a solution. Thus, the formation of the sandwich depends on the amount of molecules 30 being examined contained in the sample 19. Sometimes the immobilized binder can be “immobilized”, for example, in short-fibre cellulose, which “floats” as a suspension.
It is central in terms of the invention that the reaction is not momentary, but that it can be followed for at least seconds,—preferably for minutes, such as, for example, 30 seconds—15 minutes, more particularly 1-10 minutes, and even more particularly 1-5 minutes. The invention is based on the observation that at different moments in time the mean speed of reaction is different at different concentrations, and thus concentrations exceeding the measurement range can be identified already at an early stage in the reaction (and a different standard curve used on them than that used on samples with a lower concentration—or report that the result exceeds the measurement limit).
In addition, in the present application at the calibration data 25.1 reference is made by way of example to the calibration function's 32.1, 32.2 values, mainly due to understandability reasons. One skilled in the art will, however, understand that in reality the calibration data 25.1 can include, for example, by the fit used to form the calibration function, such as, for example, Hill's function coefficients (calibration coefficients) for different measurement's moments in time t1, t2. They are taken to the measuring device 11 along with the sets of criteria Kt1, Kt2 (limits L, H and possible categorization A-C) and the measurement moment data t1, t2. The measuring program 37 arranged in the measuring device 11 is then arranged to use this fit function applied to the calibration parameters taken, and to form on their basis the calibration curves 32.1, 32.2 used in the measurement at different moments in time t1, t2. The categorization data, i.e. how to operate in each situation, depending on on the relation of the measurement results 23 to the criterion values L, H set for each moment in time t1, t2, can also be built into the measuring program 37.
Calibration functions are referred to in connection with the invention. These can also be understood as purely response curves for different points in time. The response curve can have different functions depending on, for example, the base and the desired dynamic range. The Hill's function, for example, or also simply calibration data presented in a table form, can be used for the lateral-flow assays described as an embodiment example in the present application. A simple way to perform the method according to the invention is to compare the measurement signal to the response curves defined at the predefined time points t1, t2. Thus, in principle owing to the calibration method according to the invention a development curve as a function of time is defined for each concentration. The measurement can then be compared to a previously known curve with the aid of the (time dependent) response curves. The measurement, described above as an embodiment example, of two time points t1, t2 is a special case of this and thus the number and selection of the time points can be performed very freely, taking the invention's basic idea into account.
It should be understood that the above description and the related figures are only intended to illustrate the present invention. The invention is thus not restricted to the embodiments described above or defined in the Claims, instead many different variations and adaptations of the invention, which are possible within the scope of the inventive idea defined in the accompanying Claims, will be obvious to one skilled in the art.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20196031 | Nov 2019 | FI | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FI2020/050807 | 11/30/2020 | WO |
