The present invention relates to an analysis device for analyzing a target substance in a liquid sample, and more particularly, an analysis device which can reliably correct a measurement error of the target substance according to a degree of influence on the measurement error due to the properties of the liquid sample and the analysis element during detection of the target substance in the liquid sample, and an analysis method performed by the analysis device.
In recent years, as home health care and local health care such as hospitals and clinics have been well developed and further early diagnosis and clinical examination of high urgency have been increased, there has been an increasing demand for an analysis device with which a person, even if he/she is not a specialist in clinical examination, can execute highly precise measurement easily and speedily. Therefore, a compact analysis device for POCT (Point of Care Testing) which can perform highly reliable measurement in short time without requiring complicated operations has been highlighted.
The POCT is a generic term for examinations which are performed in “places close to patients” such as doctor's offices of practitioners and specialists, hospital wards, and clinics for ambulant patients, and this POCT attracts attention as a method that greatly contributes to improvement in the quality of medical care, by which a doctor immediately judges a test result, performs a speedily treatment, and performs up to monitoring for the process of curing as well as catamnestic monitoring. An examination by such compact analysis device can reduce costs for conveyance of analyte and facilities in contrast to an examination in a central laboratory, thereby realizing a reduction in the total examination cost. So, the POCT market is rapidly extended in the Unites States where rationalization of hospital management is progressing, and it is expected that the POCT will be a growing market from a global perspective including in Japan.
A dry analysis element represented by an immunochromatography sensor can analyze a target substance in a liquid sample such as blood or urine to be a target of measurement by only a simple operation such as dropping the liquid sample onto the analysis element without requiring adjustment of a reagent, and it is very useful for easily and speedily analyzing the target substance in the liquid sample, and therefore, a lot of dry analysis elements are put to practical use as a representative of the POCT in these days. Furthermore, higher analysis precision is demanded from the market in addition to that anybody can perform measurement anytime and anywhere.
However, the above-mentioned dry analysis element has the following drawbacks. Since liquid samples have individual differences in their properties such as viscosity, amount of each component, and foreign substance, and an analysis method using such dry analysis element is likely to be affected by these properties, and therefore, it is difficult to obtain a highly precise measurement result as compared with a large-scale analysis device which can eliminate these factors. So, analysis devices which can eliminate the above-mentioned factors that reduce the reliability of measurement have conventionally been developed by many makers.
For example, when the liquid sample is blood, there is hematocrit as a typical individual difference, and when a target substance in the blood is analyzed by the dry analysis element, the analysis is dominantly influenced by a hematocrit value in the blood. So, there have been reported various analysis devices which detect the hematocrit value and correct the concentration of the target substance according to the value by various methods (refer to Patent Document 1 to Patent Document 3).
Any of the above-mentioned methods can reliably correct a measurement error that occurs when a sample in which a hematocrit value in whole blood deviates from a normal range is measured, and it is applicable to quantitative determination for the target substance in the whole blood. However, in any method, correction is performed for only the influence of the hematocrit value, and influences due to the properties other than the hematocrit value such as the viscosity of the liquid sample or the foreign substances cannot be corrected.
On the other hand, the factor that reduces the reliability of measurement is not restricted to the above-mentioned hematocrit value, but the property such as the viscosity of the liquid sample, the analysis environment, and the deactivation of the reagent can be the factor. There has been proposed an analysis method which considers the influences on the analysis result by the factors that reduce the reliability in measurement, such as the property of the liquid sample, the analysis environment, and the deactivation of the reagent, as well as the hematocrit value. For example, there is proposed a method in which a signal that is generated when, after a specific binding reaction, a signal substance generator which relates to the specific binding and generates a signal substance diffuses in a channel and reaches detectors is measured by plural detectors that are disposed in the flow direction, and a difference or a ratio of signal modulation is obtained in each detector, thereby performing an arithmetic processing so as to minimize influences on the analysis result due to nonspecific factors other than the target substance in the liquid sample (refer to Patent Document 4).
Patent Document 1: Japanese Patent Publication No. 3586743
Patent Document 2: Japanese Published Patent Application No. 2000-262298
Patent Document 3: Japanese Published Patent Application No. 2001-91512
Patent Document 4: Japanese Published Patent Application No. Hei. 8-75718
As described above, the methods disclosed in Patent Documents 1 to 3 can reliably correct a measurement error that occurs when measuring a sample in which a hematocrit value in whole blood deviates from a normal range, and therefore, it is applicable to quantitative determination for a target substance in whole blood. However, the methods disclosed in Patent Documents 1 to 3 perform such correction for only an influence due to a hematocrit value when the liquid sample is blood, but cannot perform correction for a result that also excludes influences due to the properties derived from the liquid sample other than the hematocrit value, such as the viscosity of the liquid sample, the foreign substances in the sample, and the like, resulting in very poor measurement precision.
On the other hand, in the analysis method discloses in Patent Document 4 which considers the influences due to the factors that reduce the reliability in measurement such as the property of the liquid sample, it is premised that the plural detectors are equally subjected to the influences. However, plural stages of reactions are performed until reaching generation of a signal that becomes an indicator for minimization of the influences on the analysis result, and thereby differences in reaction states are likely to occur, and therefore, it is difficult to reliably minimize the influences. Further, the method disclosed in Patent Document 4 requires the plural detectors, and thereby the construction of the analysis device should be complicated, resulting in a problem that the complexity might be a factor that deteriorates the measurement precision, and the device is expensive in cost.
Furthermore, the above-mentioned methods cannot be introduced in a chromatography sensor which is required to be operable by anyone, anytime, and anywhere, in view of operability and construction, resulting in a lack of versatility.
Further, it is impossible for the conventional methods to automatically identify a liquid sample from among different kinds of liquid samples such as whole blood, blood plasma, urine, and the like. Therefore, it is necessary to previously indicate what liquid sample is used in a chromatography sensor, and a wrong liquid sample might be used by mistake depending on the field where it is used, and thereby an accurate result cannot be obtained. In recent years, there has frequently occurred a problem that throughout education for handlers of diagnostic agents in the fields is indispensable even through the diagnostic agents are for the POCT.
The present invention is made to solve the above-described problems and has for its object to provide an analysis device and an analysis method which can identify what liquid sample is used, and can easily obtain an analysis value with a measurement error of a target substance in the liquid sample being corrected according to a degree of influence on the measurement error due to the properties of the liquid sample and the analysis element, with which anybody can perform easy, speedy, and highly-precise measurement anytime and anywhere.
In order to solve the above-described problems, according to the present invention, there is provided an analysis device for developing a liquid sample in a channel on an analysis element and measuring a target substance in the liquid sample, which analysis device comprises a signal measurement unit for measuring a signal based on a reaction of the target substance in the liquid sample on the channel; a parameter collection unit for collecting a parameter which indicates a degree of influence on a measurement error of the target substance from the liquid sample developed on the channel; an algorithm holding unit for previously holding an algorithm comprising a relationship among the parameter, the signal, and a true value of the target substance; and an arithmetic processing unit for arithmetically processing an analysis value of the target substance from the signal on the basis of the parameter; wherein the arithmetic processing unit reads out the algorithm from the algorithm holding unit, and obtains, using the read algorithm, an analysis value of the target substance with the measurement error of the target substance being corrected on the basis of the parameter obtained in the parameter collection unit.
Therefore, it is possible to correct the measurement error of the target substance which is caused by the properties of the liquid sample and the analysis element, thereby providing a simple, speedy, and highly-accurate analysis device.
The measurement error described here is a degree of deviation of a measurement value of the target substance from a true value of the target substance, which deviation occurs due to influences of the properties of the liquid sample and the analysis element. Further, the algorithm comprises a relationship among the parameter, the signal, and the true value of the target substance. That is, the algorithm comprises a relationship between the parameter and the measurement error of the target substance, or a relationship between the signal and the true value of the target substance, which enables calculation of an analysis value of the target substance that is corrected based on the parameter. For example, the algorithm may include a numerical formula for performing an arithmetic operation on the basis of the parameter, plural numerical formulae which are prepared for selecting a degree of correction based on the parameter, and other arbitrarily methods.
Further, the parameter is numerically converted information relating to development of the liquid sample, and it may include, for example, a developing speed, a developing distance, and a developing time of the liquid sample. However, there is no problem in adopting other information such that a change of absorbance in a background that does not contribute to the reaction.
Furthermore, the influence of the properties of the liquid sample and the analysis element indicates an arbitrary influence that causes a measurement error, such as different kinds of liquid samples when the liquid sample is any of whole blood, blood plasma, urine, and bacterial cell suspending solution, or excess or shortage of the additive amount of the liquid sample, or variation in the content degree of cells in the liquid sample when the liquid sample is whole blood or bacterial cell suspending solution, or a change in the property due to the length of the storage period of the analysis element or a difference in the storage environment of the analysis element.
Further, in the analysis device of the present invention, the arithmetic processing unit includes a measurement value calculation unit for calculating a measurement value of the target substance in the liquid sample from the signal obtained in the signal measurement unit, and a measurement value correction unit for correcting the measurement value of the target substance so as to minimize the measurement error of the target substance, thereby obtaining an analysis value of the target substance; and the measurement value correction unit reads out an algorithm comprising a relationship between the parameter and the measurement error of the target substance from the algorithm holding unit, and corrects the measurement value of the target substance which is obtained in the measurement value calculation unit on the basis of the parameter obtained in the parameter collection unit by using the read algorithm, thereby obtaining an analysis value of the target substance.
Therefore, it is possible to obtain an analysis value of the target substance by correcting the measurement value of the target substance so as to minimize the measurement error of the target substance which is caused by the properties of the liquid sample and the analysis element, thereby providing a simple, speedy, and highly-accurate analysis device.
Further, in the analysis device of the present invention, the analysis element includes a sample application part for applying the liquid sample onto the channel, a marker reagent part which holds a marker reagent that reacts with the target substance so that the marker reagent can be eluted by development of the liquid sample, and a sample immobilization part which immobilizes and holds a reagent that comprehends the degree of the reaction between the target substance and the marker reagent.
Therefore, an accurate analysis value of the target substance in the liquid sample can be easily and speedily obtained.
Further, in the analysis device of the present invention, the parameter is any of a developing speed, a developing time, and a developing distance which are obtained when the liquid sample is developed on the channel.
Therefore, the developing state of the liquid sample which is influenced by a difference in the properties of the liquid sample and the analysis device can be detected more accurately and quantitatively. By using this developing state, a speedy and simple analysis device having higher accuracy and versatility can be obtained.
Further, in the analysis device of the present invention, at least one of the signal measurement unit and the parameter collection unit uses electromagnetic radiation.
Therefore, it becomes possible to detect the degree of minute modulation in the signal on the channel, thereby providing an analysis device having higher precision and accuracy.
Further, in the analysis device of the present invention, the analysis element is a dry type analysis element.
Therefore, the analysis device is easy to carry because the entire analysis element is a dry carrier, and further, it is easy to handle because there is no necessity of strictly controlling the storage environment and storage condition, thereby providing a speedy, simple, and highly-accurate analysis device anytime and anywhere.
Further, in the analysis device of the present invention, the signal measurement unit measures a signal based on a reaction that is derived from an antigen-antibody reaction.
Since the antibody can be artificially created, the target that can be detected in this analysis device is diversified, and thereby measurement of various kinds of target substances can be carried out. Further, an analysis device of higher accuracy can be provided by making use of a specific reaction of the antibody.
Further, in the analysis device of the present invention, the analysis element is an immunochromatography sensor.
Therefore, it is possible to realize a high accuracy which prevents a user from performing erroneous judgment, and a simple operation which can be used by anyone, anytime and anywhere.
Further, in the analysis device of the present invention, the analysis element is a one-step immunochromatography sensor.
Therefore, it is possible to provide a simple, speedy, and highly-accurate analysis device which does not require complicated operations such as pretreatment and washing, even using a immunoassay method.
Further, in the analysis device of the present invention, the channel comprises a monolayer or multilayer porous material.
Therefore, it becomes possible to reliably hold the reagent in the channel and develop the liquid sample, thereby providing a simple, speedy, and highly-accurate analysis device in analysis of the liquid sample.
Further, in the analysis device of the present invention, the algorithm holding unit holds a correction formula for correcting the measurement value of the target substance on the basis of the parameter; and the measurement value correction unit reads out the correction formula from the algorithm holding unit, and corrects the measurement value of the target substance using the read correction formula and the parameter, thereby obtaining an analysis value of the target substance.
Therefore, the measurement error of the target substance due to the properties of the liquid sample and the analysis element can be easily corrected, and thereby a more accurate analysis value of the target substance can be speedily and easily obtained.
Further, in the analysis device of the present invention, the algorithm holding unit holds a plurality of the correction formulae; the analysis device further includes an algorithm selection unit for selecting any of the plural correction formulae that are stored in the algorithm holding unit on the basis of the measurement value of the target substance; and the measurement value correction unit corrects the measurement value of the target substance using the correction formula selected by the algorithm selection unit and the parameter, thereby obtaining an analysis value of the target substance.
Therefore, the measurement error of the target substance due to the properties of the liquid sample and the analysis element can be corrected using a correction formula that is selected according to the measurement value of the target substance from among the plural correction formulae, and thereby a more accurate analysis value of the target substance can be speedily and easily obtained.
Further, in the analysis device of the present invention, the algorithm holding unit holds a plurality of calibration curves for obtaining an analysis value of the target substance with the measurement error of the target substance being corrected, from the signal obtained in the signal measurement unit; the analysis device further includes an algorithm selection unit for selecting any of the plural calibration curves that are stored in the algorithm holding unit on the basis of the parameter; and the arithmetic processing unit obtains an analysis value of the target substance with the measurement error of the target substance being corrected, from the signal by using the calibration curve selected by the algorithm selection unit and the parameter.
Therefore, the assumed measurement error of the target substance due to the properties of the liquid sample and the analysis device can be minimized by using a calibration curve that is selected according to the parameter from among the plural calibration curves, and thereby a more accurate analysis value of the target substance can be obtained speedily and easily.
Further, in the analysis device of the present invention, the arithmetic processing unit obtains an analysis value of the target substance with the measurement error of the target substance due to an influence of the viscosity of the liquid sample, or the additive amount of the liquid sample, or the passage time after fabrication of the analysis element being corrected.
Therefore, an accurate analysis value of the target substance in the liquid sample can be obtained regardless of whatever property or additive amount the liquid sample has. Further, it is possible to avoid an influence of deterioration of the analysis element due to passage time after manufacturing.
Further, according to the present invention, there is provided an analysis method for developing a liquid sample in a channel on an analysis element, and measuring a target substance in the liquid sample, which method comprises a parameter collection step of collecting a parameter which indicates a degree of influence on a measurement error of the target substance, from the liquid sample developed on the channel; a signal measurement step of measuring a signal based on a reaction of the target substance in the liquid sample on the channel; and an arithmetic processing step of reading out an algorithm from an algorithm holding unit which previously holds an algorithm comprising a relationship among the parameter, the signal, and a true value of the target substance, and obtaining, using the read algorithm, an analysis value of the target substance with the measurement error of the target substance being corrected on the basis of the parameter obtained in the parameter collection unit.
Therefore, the measurement error of the target substance due to the properties of the liquid sample and the analysis element can be easily corrected, thereby obtaining a highly accurate analysis value.
Further, in the analysis method of the present invention, the arithmetic processing step includes a measurement value calculation step of calculating a measurement value of the target substance in the liquid sample from the signal obtained in the signal measurement step, and a measurement value correction step of correcting the measurement value of the target substance to obtain an analysis value of the target substance.
Therefore, it is possible to obtain a more accurate analysis value by correcting the measurement value of the target substance so as to remove the measurement error of the target substance due to an influence of the properties of the liquid sample and the analysis element.
According to the present invention, when performing measurement of a target substance in a liquid sample, a parameter which indicates a degree of influence on a measurement error of the target substance due to the properties of the liquid sample and the analysis element is collected from the liquid sample that is developed on a channel on the analysis element, and the measurement error of the target substance in the liquid sample is corrected according to the parameter. Thereby, a highly accurate analysis value of the target substance can be obtained easily and speedily.
a) is a conceptual diagram of hCG quantification according to the sixth example of the present invention.
b) is a conceptual diagram of hCG quantification according to the sixth example of the present invention.
c) is a flowchart of hCG quantification according to the sixth embodiment of the present invention.
Hereinafter, embodiments of analysis devices according to the present invention will be described in detail with reference to the drawings. However, the embodiments described below are merely examples, and the present invention is not restricted thereto.
The measurement error of the target substance indicates a degree of deviation of the measurement value of the target substance that is calculated from the signal measured by the signal measurement unit 20, from the true value of the target substance, which deviation is caused by influences of the properties of the liquid sample and the analysis element 100. Further, the algorithm comprises a relationship between the parameter and the measurement error of the target substance or a relationship between the signal and the true value of the target substance, and it enables calculation of an analysis value of the target substance which is corrected based on the parameter. For example, the algorithm may include a numerical formula for performing an arithmetic operation on the basis of the parameter, and plural numerical formulae which are prepared for selecting a degree of correction based on the parameter, and further, other arbitrarily methods. Further, the parameter is numeric-converted information relating to development of the liquid sample, and it may include, for example, a developing speed, a developing distance, and a developing time of the liquid sample. However, there is no problem in adopting information other than mentioned above, such as a change of absorbance in a background that does not contribute to the reaction.
Further, while in
First of all, the analysis element 100 according to the first embodiment will be described.
In
Reference numeral 2 denotes a marker reagent part in which a gold colloid marker antibody against the target substance in the liquid sample is held in its dry state so as to be dissolvable by development of the liquid sample. The marker reagent is obtained by labeling an antibody with a marker such as gold colloid, and it is used as a means for detecting bindings in reagent immobilization parts 3 and 4 which are described later. The gold colloid is merely an example, and any material may be arbitrarily selected according to need from among, for example, metal or nonmetal colloid particle, enzyme, protein, dye, fluorescent dye, and colored particle such as latex.
Reference numerals 3 and 4 denote a reagent immobilization part I and a reagent immobilization part II, respectively, which are antibodies that can specifically react against the target substance in the liquid sample. Both the antibodies are bound to the target substance with epitopes different from that of the marker reagent, and they are immobilized in their dry states. Further, the antibody used for the reagent immobilization part I and the antibody used for the reagent immobilization part II have different affinities to the target substance in the liquid sample.
The antibodies used for the reagent immobilization part I and the reagent immobilization part II have only to form complexes with the marker reagent and the target substance, and therefore, the epitopes or the affinities of the antibodies for the target substance may be the same or different from each other. Further, the two antibodies may have the same epitope while they have different affinities.
Furthermore, while in
Reference numeral 5 denotes a liquid impermeable sheet, and it comprises a transparent tape in this first embodiment. The liquid impermeable sheet 5 has a configuration to hermetically cover the developing layer 1, except a portion contacting a fine space 6 serving as a sample application part, and an end portion to which the liquid sample reaches.
As described above, the liquid impermeable sheet 5 that covers the developing layer 1 has a function of blocking spot-application of the liquid sample onto a part other than the sample application as well as preventing contamination from the outside, and furthermore, it prevents the liquid sample from being evaporated while it is developed, whereby the liquid sample always passes through the reagent immobilization parts 3 and 4 and the marker reagent part 2 which are reaction parts on the developing layer, and thus reactions with the target substance in the liquid sample can be efficiently carried out in the reaction parts. The contamination from the outside indicates an accidental contact of the liquid sample to the reaction parts on the developing layer, or a direct touch of a patient's hand or the like to the developing layer. Preferably, a transparent material is used as the liquid impermeable sheet 5 that covers the developing layer 1, and at least portions of the sheet 5 covering the reagent immobilization parts 3 and 4 are desired to be transparent because these parts 3 and 4 measure a signal.
Further, when more accurate measurement is required, an upper portion of the developing layer 1, particularly including the marker reagent part 2 and the reagent immobilization parts 3 and 4, may be hermetically sealed and, further, side surfaces parallel to the liquid sample developing direction may be hermetically sealed as well.
Reference numeral 7 denotes an open part in the developing layer 1, and reference numeral 8 denotes a substrate which supports the developing layer 1. The substrate 8 comprises a liquid impermeable sheet such as a PET film, and it may be any of transparent, semitransparent, and nontransparent. However, it is desirable to adopt a transparent material when measuring transmitted light, and a nontransparent material when measuring reflected light. The materials may include synthetic resins such as ABS, polystyrene, and polyvinyl chloride, and liquid impermeable materials such as metal and glass.
The substrate 8 has a function of reinforcing the developing layer 1, and a function of blocking the sample when a sample having a risk of infection such as blood, saliva, or urine is used. Further, when there is a possibility that the developing layer 1 becomes to have optical transparency when it is wetted, the substrate 8 may have an effect of blocking light.
Reference numeral 9 denotes a fine space formation member, having a function of forming a space into which the liquid sample flows due to a capillary phenomenon, and comprising laminated transparent PET films. The fine space formation member 9 also has a function of avoiding contamination of the exterior by the liquid sample when handling the analysis element after application of the liquid sample. The fine space formation member 9 may comprise a synthetic resin material such as ABS, polystyrene, or polyvinyl chloride, or a liquid impermeable material such as metal or glass. While the fine space formation member 9 is desired to be transparent or semitransparent, it may be nontransparent and colored, and it may be composed of an arbitrary nontransparent material.
Reference numeral 6 denotes a fine space. The fine space 6 is formed by the fine space formation member 9, and serves as a sample application part into which the liquid sample is introduced by a capillary phenomenon. The fine space 6 is connected with the developing layer 1, and development of the liquid sample onto the developing layer 1 can be started by introducing the liquid sample into the fine space 6.
Next, a method for measuring the target substance in the liquid sample by the analysis device 60 according to the first embodiment will be described with reference to
When the liquid sample is brought into contact with the fine space 6, the liquid sample naturally flows into the fine space 6 by a capillary phenomenon without the necessity of mechanical operation, and the liquid sample is developed on the developing layer (channel) 1. Whether the flow amount of the liquid sample is sufficient or not can be checked through the fine space formation member 9. When it is necessary to ensure a predetermined additive amount of the liquid sample, the additive amount can be precisely restricted by setting the volume of the fine space 6 to a predetermined volume. Further, when more than a predetermined amount of the liquid sample is required, a structure which holds a volume larger than the required amount is adopted to realize this.
A cell component contraction reagent 10 is stored in the fine space 6. The cell component contraction reagent 10 is a reagent to be provided when cell components are included in the liquid sample, and therefore, it is not especially needed when using a liquid sample including no cell components. Further, the cell component contraction reagent 10 may be any reagent having an effect of contracting cells, such as inorganic compounds including potassium chloride, sodium chloride, and sodium phosphate salt, or amino acids such as glycine and glutamic acid, or imino acids such as proline, or sugars such as glucose, sucrose, and trehalose, or sugar alcohols such as glucitole. A system including such cell component contraction reagent 10 is especially effective when whole blood is used as a liquid sample.
The liquid sample introduced into the fine space 6 is developed from the contact portion of the fine space 6 and the developing layer 1 onto the developing layer 1. When the liquid sample reaches the marker reagent part 2, dissolution of the marker reagent is started. When the target substance exists in the liquid sample, development is promoted while the marker reagent and the target substance react with each other, and the liquid sample reaches the reagent immobilization part I3. When the target substance exists in the liquid sample, complexes of the antibody immobilized to the reagent immobilization part I3, the target substance, and the marker reagent are formed in accordance with the amount of the target substance.
Next, the liquid sample reaches the reagent immobilization part II4. When the target substance exists in the liquid sample, complexes of the antibody immobilized to the reagent immobilization part II4, the target substance, and the marker reagent are formed in accordance with the amount of the target substance.
Further, the liquid sample reaches the open part 7 in the developing layer 1. Since the open part 7 is opened without being covered with the liquid impermeable sheet 5, the liquid sample is volatilized or evaporated after it has reached or while reaching the open part 7. Further, the liquid sample exudes onto the open part 7, and only the liquid sample on the developing layer 1 at the open part 7 reaches up to the same height or the approximate height as the liquid sample existing on the developing layer 1 in the fine space 6. Generally, an absorption part is often provided instead of the open part. The reason is as follows. When a porous material having a higher water-holding effect or an absorption effect than that of the material of the developing layer 1 is adopted for the absorption part, the absorption part absorbs or sucks the liquid sample, thereby providing a function of making the sample pass on the developing layer 1, and a function of reducing the measurement time. The open part 7 has the same effects as those of the absorption part, and particularly the technique of using the fine space 6 or the open part 7 is suitable for a case where the liquid sample is very small in quantity such as blood obtained by piercing a fingertip.
A measurement value of the target substance in the liquid sample is obtained by measuring a signal derived from the marker reagent in the reagent immobilization part I3 and the reagent immobilization part II4.
The irradiation part 21 is desired to be a visible area or an approximately visible area, and an LED (Light Emitting Diode) or an LD (Laser Diode) can be selected according to need.
Then, the marker-reagent-derived signal in the reagent immobilization parts 3 and 4 which is measured by the signal measurement part 20 is arithmetically processed in the measurement value calculation unit 70 to obtain a measurement value of the target substance. The measurement value of the target substance thus obtained is a value of the target substance which is obtained from the marker-reagent-derived signal obtained in the signal measurement unit 20 by using a calibration curve. The calibration curve is a regression formula indicating a relationship between the signal obtained by the signal measurement unit 20 and the value of the target substance in the liquid sample. When measuring a liquid sample including an unknown amount of target substance, a measurement value of the target substance in the liquid sample can be calculated by substituting the signal obtained by the signal measurement unit 20 into the formula. Further, the signal measurement unit 20 may use an arbitrary means for measuring a signal, such as a means for reading an optical change, an electric change, or a magnetic change, or a means for capturing the signal as an image.
Further, while the above-mentioned reaction is a sandwich reaction utilizing an antigen-antibody reaction, a reaction system utilizing a competition reaction may be adopted by selecting a reagent.
Furthermore, when it is desired to utilize a specific reaction, measurement by a reaction other than the antigen-antibody reaction can be performed by constituting with a reagent component of a system that forms an arbitrary reaction on the analysis element 100. As for a combination of a specific substance and a specific binding substance which perform a specific reaction, there are an antigen and an antibody thereto, complementary nucleic acid sequences, an effector molecule and a receptor molecule, an enzyme and an inhibitor, an enzyme and a cofactor, an enzyme and a ground substance, a compound having a sugar change and a lectin, an antibody and an antibody thereto, a receptor molecule and an antibody thereto, a reaction system that is chemically modified to an extent that specific binding activity is not lost, and a reaction system utilizing a complex substance that is obtained by binding with another component. However, it is hard to say that the measurement value of the target substance which is obtained by the measurement value calculation unit 70 as described above has a high precision, because it is affected by the properties of the liquid sample and the analysis element 60. Accordingly, in order to obtain a highly precise analysis value of the target substance, correction of the measurement value described hereinafter is required.
Hereinafter, a description will be given of a method for obtaining an analysis value of the target substance with a measurement error of the target substance being corrected, from the measurement value of the target substance. The correction method described hereinafter is merely an example, and there will be no problem in using other methods. As a parameter indicating a degree of influence to the measurement error of the target substance, a developing speed of the liquid sample is adopted. Further, it is possible to utilize, as a parameter, another information relating to the developing state of the liquid sample, such as a developing time required for developing an arbitrary constant distance, or a developing distance in an arbitrary constant time, or a change in absorbance of a background at an arbitrary position excluding the reagent immobilization parts on the channel.
In this first embodiment, the parameter collection unit 30 for collecting the above-mentioned parameters detects the developing state of the liquid sample by detecting an optical change using the irradiation part 31 and the light-receiving part 32. An arbitrary means other than mentioned above such as a means for reading an electric change or a magnetic change or a means for capturing such change as an image may be adopted. The arrival times of the liquid sample may be simultaneously detected using plural irradiation parts and plural light-receiving parts, or the arrival times may be measured by detecting arrival of the liquid sample to the start point and then detecting successive migrations of the liquid sample to the end point by using the same irradiation part and the same light-receiving part. Further, the irradiation part 21 and the light-receiving part 22 of the signal measurement unit 20 for measuring a signal derived from the marker reagent may be used as the irradiation part 31 and the light-receiving part 32 of the parameter collecting part 30.
In
In
As shown in
Next, the arithmetic processing unit 90 reads the algorithm from the algorithm holding unit 40, and obtains an analysis value of the target substance with the measurement error of the target substance being corrected on the basis of the parameter obtained in the parameter collection unit 30. The analysis value of the target substance is a value of the target substance which is obtained in the arithmetic processing unit 90 by correcting the measurement error of the target substance so as to minimize a difference from the true value of the target substance on the basis of the parameter obtained in the parameter collection unit 30. The algorithm is a formula for obtaining an analysis value of the target substance by correcting the measurement error of the target substance, which formula is derived from the relationship between the parameter obtained in the parameter collection unit 30 and the measurement error of the target substance, or an correction formula which is derived from the relationship between the signal obtained in the signal measurement unit 20 on the basis of the parameter and the true value of the target substance. There are various kinds of algorithm deriving methods. Although correction methods described hereinafter are preferable as simple and highly precise methods, there is no problem in adopting other methods.
Method 1) As shown in
Y=Z÷{1+(aX+b)}; (a,b: constants)
The above correction formula is a numerical formula which is previously derived from the relationship between the parameter and the measurement error by using a liquid sample including an known amount of target substance and having a different degree of influence to the measurement error such as the viscosity of the liquid sample. Thereafter, when measuring a liquid sample including an unknown amount of target substance, it is possible to obtain an analysis value of the target substance by correcting the measurement value of the target substance from the obtained parameter.
Method 2) As shown in
Method 3) As shown in
Further, as for the algorithm holding part 40 which holds the algorithm to be read out when the arithmetic processing unit 90 performs correction, it may be incorporated in the analysis device 60 as a circuit, or it may be convertibly stored by using a storage medium or the like, or it may be input to the analysis device 60 at measurement and made to perform operation after measurement to display the analysis value of the target substance. However, there is no problem in using other methods. Further, it is also possible to adopt a method of inputting a specific constant to the analysis device 60 or the analysis element 100 for a correlation formula that is previously incorporated in the analysis device 60 as a circuit, and this method is preferable in considering the lot difference of the analysis device 60 or the analysis element 100. When part or all of the constant parts of the function depends on the lot of the analysis device 60 or the analysis element 100, these constant parts are set in the device before analysis is started, thereby eliminating an influence due to the lot difference of the analysis device 60 or the analysis element 100. Further, while in
Examples of major factors of measurement errors which can be corrected by the analysis device 60 of the present invention will be described hereinafter. By performing correction with considering the measurement error factors I, it is possible to reduce deterioration in precision due to the measurement error factors II and III.
Types of Liquid Samples
e.g., whole blood, blood plasma, blood serum, urine, bacterial cell suspending solution, etc.
Characteristics of Liquid Samples
e.g., viscosity of the liquid sample, amount of formed element, hematocrit value when the liquid sample is whole blood, total protein concentration, etc.
Additive Amount of Liquid Sample
e.g., excess or shortage of additive amount, deficient additive amount, etc.
e.g., change in activity of the reagent relating to specific binding, change in property of the material of such as the developing layer that forms a channel, imperfect development of the liquid sample due to dust or contamination on the channel
e.g., temperature and humidity during measurement
The fluidity of the liquid sample varies due to these measurement error factors, and thereby differences occur in the reaction time, which adversely affect the precision of the measurement value of the target substance. For example, as an influence on the measurement error of the liquid sample due to the property of the liquid sample, as shown in
As described above, according to the analysis device of the first embodiment of the present invention, when measuring a target substance in a liquid sample, a measurement error of the target substance is easily corrected according to a degree of influence on the measurement error due to the property of the liquid sample or the analysis device to obtain an analysis value of the target substance. Therefore, it is possible to provide a simple, speedy, and highly-precise analysis device.
Methods for executing the present invention will be described in more detail using the following examples. However, the present invention is not restricted to the following examples.
An immunochromatography sensor as an analysis element including a reagent immobilization part I obtained by immobilizing anti-CRP antibody A on a nitrocellulose film, a reagent immobilization part II obtained by immobilizing anti-CRP antibody B on the nitrocellulose film, and a marker reagent part holding complexes of anti-CRP antibody C and gold colloid (marker reagent) was manufactured. This immunochromatography sensor is shown in
An anti-CRP antibody A solution whose concentration is adjusted by dilution with a phosphate buffer solution was prepared. This antibody solution was applied on a nitrocellulose film by using a solution discharge unit. Thereby, an immobilized antibody line I3 as a reagent immobilization part was obtained on the nitrocellulose film. Next, similarly, an anti-CRP antibody B solution was applied to a portion that is apart by 2 mm downstream from the sample application part. After this nitrocellulose film was dried, it was immersed in a Tris-HCl buffer solution containing 1% skim milk, and shaken gently for 30 minutes. After 30 minutes, the film was moved into a Tris-HCl buffer solution tank and shaken gently for 10 minutes, and thereafter, it was shaken gently for another 10 minutes in another Tris-HCl buffer solution tank, thereby washing the film. Next, the film was immersed in a Tris-HCI buffer solution containing 0.05% sucrose monolaurate, and shaken gently for ten minutes. Thereafter, the film was taken out of the solution tank, and dried at room temperature. Thus, the immobilized antibody line I3 and the immobilized antibody line II4 as reagent immobilization parts were obtained on the nitrocellulose film.
The gold colloid was prepared by adding a 1% citric acid solution to a 0.01% chlorauric acid 100° C. solution that is circulated. After the circulation was continued for 30 minutes, the solution was cooled by being left at room temperature. Then, the anti-CRP antibody C was added to the gold colloid solution that is adjusted to pH8.9 with a 0.2M potassium carbonate solution, and the solution was shaken for several minutes. Thereafter, a 10% BSA (bovine serum albumin) solution of pH8.9 was added to the solution by such an amount that the concentration thereof finally becomes 1%, and the solution was stirred, thereby preparing antibody-gold colloid complexes (marker antibody). The marker antibody solution was subjected to centrifugation at 4° C. and 20000 G for 50 minutes to isolate the marker antibody, and then the marker antibody was suspended in a washing buffer solution (1% BSA 5% sucrose.phosphoric acid solution), and subjected to centrifugation to wash and isolate the marker antibody. The marker antibody was suspended in a washing buffer solution, and filtered with a 0.8 μm filter, and thereafter, adjusted so that the absorbance at 520 nm becomes 150, and then stored at 4° C. The marker antibody solution was set in a solution discharge device, and applied to a position apart from the immobilized line I and the immobilized line II on the dried film to which the immobilization anti-CRP antibody A and the immobilization anti-CRP antibody B are applied so as to have a positional relationship of the marker antibody, the immobilized line I, and the immobilized line II arranged in this order from the liquid sample application start position, and thereafter, the film was subjected to vacuum freeze dry. Thereby, a reaction layer carrier having the reagent immobilization parts and the marker reagent part was obtained.
Next, the reaction layer carrier including the prepared marker reagent was bonded to a substrate 8 comprising a 0.5 mm thick white PET, and a transparent tape was bonded thereto from the marker reagent part 2 to the end part. Thereafter, the substrate 8 was cut into widths of 2.0 mm using laser. After the cutting, a fine space formation member 9 formed by laminating 100 μm thick transparent PET was bonded onto the front end portion where the transparent tape is not bonded, thereby forming a fine space 6 (width 2.0 mm×length 12.0 mm×height 0.5 mm). A 10% potassium chloride solution was previously applied to the space formation member 9, and then the space formation member 9 was quickly frozen by liquid nitrogen and freeze-dried, thereby forming the space formation member which holds the cell contraction agent that is potassium chloride being held in its dry state. Thus, the immunochromatography sensor was manufactured.
CRP solutions of known concentrations were added to human blood to which heparin was added as an anticoagulant, thereby preparing blood having CRP concentrations of 0.6 mg/dL and 5 mg/dL. Further, the total protein concentration was set to 7.5 g/dL, and the hematocrit value was adjusted to 20%, 30%, 40%, and 50%.
The whole blood containing CRP which was prepared in the step b) was applied by about 5 μL to the sample application part of the immunochromatography sensor, and developed toward the open part to promote an antigen-antibody reaction. The coloration status on the antibody immobilized part after 5 minutes from the sample application to the immunochromatography sensor was measured.
Next, the reflection absorbances obtained in the reagent immobilization part I3 and the reagent immobilization part II4 were substituted in the respective calibration curves that have been prepared, thereby obtaining the CRP concentrations.
d) Selection of Detection Section where Parameter is Collected
Hereinafter, selection of a detection section for a developing speed as a parameter will be described. Using the irradiation part 31 and the light-receiving part 32 of the parameter collection unit 30 shown in
Initially, the detection section for the developing speed as a parameter is varied to 0.5, 4.0, 7.5, 20.0 mm, and the developing speeds of the liquid sample in the respective distances were calculated. Next, the reflection absorbances obtained at the reagent immobilization part I and the reagent immobilization part II were substituted in the prepared calibration curves to calculate measurement values of expected CRP concentrations, and degrees of deviation from the true value of the CRP concentration of the liquid sample used in this measurement were obtained. The relationship between the developing speeds and the deviation degrees is shown in
For example, when the parameter detection section is 4.0 mm, the correlation equation between the developing speed x and the deviation degree y is represented by the following formula (1).
y=26.258x−2.7281 (1)
Based on this correlation equation, a numerical formula for correcting the CRP concentration from the developing speed can be derived. Assuming that the measurement value of the CRP concentration is Z, a correction formula for obtaining an analysis value Y of the CRP concentration is represented by the following formula (2).
Y=Z÷{1+(26.258x−2.7281)} (2)
Here, an area of 20.0 mm from the start end to the middle of the channel in which the correlation between the developing speed and the deviation degree was largest in the inspection of the detection section in step d) was adopted as a detection section, and a correction formula that is derived from the correlation between the developing speed of the liquid sample in this detection section and the degree of deviation from the true value of the CRP concentration was used. The correlation formula was used separately for the case where the measurement value is less than 11.0 mg/dL and the case where it is equal to or larger than 11.0 mg/dL. Assuming that the measurement value of the CRP concentration is Z and the developing speed is x, correction formulae for obtaining analysis values Y of the CRP concentration were represented by the following formulae 3 and 4.
When the measurement value is less than 11.0 mg/dL;
Y=Z÷{1+(6.3589x−1.3949)} (3)
When the measurement value is equal to or larger than 1.0 mg/dL;
Y=Z÷{1+(3.8233x−0.61879)} (4)
The algorithm selection unit 80 selects any of the correction formulae stored in the algorithm holding unit 40 according to the measurement value of the CRP concentration, and the measurement value correction unit 50 substitutes the parameter and the measurement value into the selected correction formula, whereby the measurement value of the CRP concentration was corrected and an analysis value of the CRP concentration was obtained. A flowchart thereof is shown in
An immunochromatography sensor as an analysis element including a reagent immobilization part I obtained by immobilizing anti-CRP antibody A on a nitrocellulose film, a reagent immobilization part II obtained by immobilizing anti-CRP antibody B on the nitrocellulose film, and a marker reagent part holding complexes of anti-CRP antibody C and gold colloid (marker reagent) was manufactured. This immunochromatography sensor is shown in
The following measurement was performed using a sensor in the same lot as the immunochromatography sensor used in the first example.
CRP solutions of known concentrations were added to human blood to which heparin was added as an anticoagulant, thereby preparing blood having CRP concentrations of 0.6 mg/dL and 5 mg/dL. Further, the hematocrit value was set to 40%, and the total protein concentration was adjusted to 2.5 g/dL, 5 g/dL, 7.5 g/dL, 10 g/dL, and 12.5 g/dL.
The whole blood containing CRP which was prepared in the step b) was applied by about 5 μL to the sample application part of the immunochromatography sensor, and measurement values of the CRP concentrations were calculated by the same method as described for the first example.
The measurement values of the CRP concentrations were corrected on the basis of the correction formula derived in the above-described first example to obtain an analysis value of the CRP concentration.
By using this correction formula, in a blood sample having a hematocrit value of 14.9˜51%, a total protein concentration of 4.2˜10 g/dL, and an albumin concentration of 1.4˜4.9%, the measurement precision was significantly improved, and a correction effect against the influences of the properties of the blood sample was clearly recognized.
An immunochromatography sensor as an analysis element including a reagent immobilization part I obtained by immobilizing anti-CRP antibody A on a nitrocellulose film, a reagent immobilization part II obtained by immobilizing anti-CRP antibody B on the nitrocellulose film, and a marker reagent part holding complexes of anti-CRP antibody C and gold colloid (marker reagent) was manufactured. This immunochromatography sensor is shown in
The following measurement was performed using a sensor in the same lot as the immunochromatography sensor used in the first example.
A CRP solution of a known concentration was added to human blood to which heparin was added as an anticoagulant, thereby preparing blood having a CRP concentration of 5 mg/dL. Further, the total protein concentration was set at 7.5 g/dL, and the hematocrit value was adjusted to 30%, 40%, and 50%.
The whole blood including CRP which was prepared in the step b) was applied to the sample application part of the immunochromatography sensor by amounts of 4 μL, 4.25 μL, 4.5 μL, and 4.75 μL which are shorter than the standard additive amount of the liquid sample and by an amount of about 5 μL which is the standard additive value of the liquid sample, and measurement values of CRP concentrations were calculated by the same method as adopted in the first example.
The measurement values of the CRP concentrations were corrected on the basis of the correction formula derived in the above-described first example to obtain an analysis value of the CRP concentration.
By using this correction formula, the precision was significantly improved in the measurement in which the measurement results deviated to lower values due to shortage in the additive amount of the liquid sample, and a correction effect against the influence of the shortage in the additive amount of the liquid sample was clearly recognized. By using this correction method, it is possible to avoid a reduction in sensitivity due to shortage in the additive amount.
An immunochromatography sensor as an analysis element including a reagent immobilization part I obtained by immobilizing anti-CRP antibody A on a nitrocellulose film, a reagent immobilization part II obtained by immobilizing anti-CRP antibody B on the nitrocellulose film, and a marker reagent part holding complexes of anti-CRP antibody C and gold colloid (marker reagent) was manufactured. This immunochromatography sensor is shown in
The following measurement was performed using a sensor in the same lot as the immunochromatography sensor used in the first example.
CRP solutions of known concentrations were added to human blood to which heparin was added as an anticoagulant, thereby preparing blood having CRP concentrations of 0.6 mg/dL and 5 mg/dL. Further, the hematocrit value and the total protein concentration were set to 20%·4 g/dL, 30%·5.5 g/dL, 40%·7 g/dL, 50%·8.5 g/dL, 60%·10 g/dL, 30%·8.5 g/dL, and 50%·5.5 g/dL.
The whole blood containing CRP which was prepared in the step b) was applied by about 5 μL to the sample application part of the immunochromatography sensor, and measurement values of the CRP concentrations were calculated by the same method as described for the first example.
The developing time of the liquid sample in an arbitrary section on the developing layer and the absorbances at the reagent immobilization parts I3 and II4 were measured using the irradiation part 31 and the light-receiving part 32 of the parameter collection unit 30 shown in
Based on the correlation equation between the developing speed and the deviation degree, a numerical formula for correcting the measurement value of the CRP concentration from the developing speed was derived. Assuming that the measurement value of the CRP concentration is Z and the developing speed is x, a correction formula for obtaining an analysis value Y of the CRP concentration is represented by the following formula (5).
Y=Z÷{1+(1.2825 Ln(x)−2.57000)} (5)
The measurement value of the CRP concentration was corrected by the measurement value correction unit 50 to obtain an analysis value of the CRP concentration. The result was shown in
An immunochromatography sensor as an analysis element including a reagent immobilization part I obtained by immobilizing anti-CRP antibody A on a nitrocellulose film, a reagent immobilization part II obtained by immobilizing anti-CRP antibody B on the nitrocellulose film, and a marker reagent part holding complexes of anti-CRP antibody C and gold colloid (marker reagent) was manufactured. This immunochromatography sensor is shown in
The following measurement was performed using a sensor in the same lot as the immunochromatography sensor used in the first example.
CRP solutions of known concentrations were added to human blood to which heparin was added as an anticoagulant, thereby preparing blood having CRP concentrations of 0.6 mg/dL and 5 mg/dL. Further, the hematocrit value and the total protein concentration were adjusted to 20%·4 g/dL, 30%·5.5 g/dL, 40%·7 g/dL, 50%·8.5 g·dL, 60%·10 g/dL, 30%·8.5 g/dL, and 50%·5.5 g/dL.
The whole blood containing CRP which was prepared in the step b) was applied by about 5 μL to the sample application part of the immunochromatography sensor, and reflection absorbances at the reagent immobilization parts 3 and 4 were measured by the signal measurement unit 20.
The developing time of the liquid sample in an arbitrary section on the developing layer and the reflection absorbances at the reagent immobilization parts I3 and II4 were measured using the irradiation part 31 and the light-receiving part 32 of the parameter collection unit 30 shown in
When the developing speed is less than 0.100 mm/s;
Y=10{(Log(z)−0.1363)/−0.5663} (6)
When the developing speed is equal to or larger than 0.100 mm/s and less than 0.110 mm/s;
Y=10{(Log(z)−0.2642)/−0.4162} (7)
When the developing speed is equal to or larger than 0.110 mm/s and less than 0.120 mm/s;
Y=10{(Log(z)−0.3185)/−0.4628} (8)
When the developing speed is equal to or larger than 0.120 mm/s and less than 0.130 mm/s;
Y=10{(Log(z)−0.3661)/−0.3937} (9)
When the developing speed is equal to or larger than 0.130 mm/s;
Y=10{(Log(z)−0.4168)/−0.3233} (10)
Any of the plural calibration curves stored in the algorithm holding unit 40 was selected according to the developing speed by the algorithm selection unit 80, and the signal (reflection absorbance) obtained by the signal measurement unit 20 was substituted in the selected calibration curve by the arithmetic processing unit 90, thereby obtaining an analysis value of the CRP concentration. The result is shown in
An immunochromatography sensor as an analysis element including a reagent immobilization part I obtained by immobilizing anti-hCG antibody A on a nitrocellulose film, a reagent immobilization part II obtained by immobilizing anti-hCG antibody B on the nitrocellulose film, and a marker reagent part holding complexes of anti-hCG antibody C and gold colloid was manufactured. This immunochromatography sensor is shown in
An anti-hCG antibody A solution whose concentration was adjusted by dilution with a phosphate buffer solution was prepared. This antibody solution was applied onto a nitrocellulose film by using a solution discharge unit. Thereby, an immobilized antibody line I3 as a reagent immobilization part was obtained on the nitrocellulose film. Next, similarly, an anti-hCG antibody B solution was applied to a part that is apart by 2 mm to the lower stream side from the sample application part. After this nitrocellulose film was dried, it was immersed in a Tris-HCl buffer solution containing 1% skim milk, and shaken gently for 30 minutes. After 30 minutes, the film was moved into a Tris-HCl buffer solution tank and shaken gently for 10 minutes, and thereafter, it was shaken gently for another 10 minutes in another Tris-HCl buffer solution tank, thereby washing the film. Next, the film was immersed in a Tris-HCI buffer solution containing 0.05% sucrose monolaurate, and shaken gently for ten minutes. Thereafter, the film was taken out of the solution tank, and dried at room temperature. Thereby, an immobilized antibody line I3 and an immobilized antibody line II4 as reagent immobilization parts were obtained on the nitrocellulose film.
The gold colloid was prepared by adding a 1% citric acid solution to a 0.01% chlorauric acid 100° C. solution that is circulated. After the circulation was continued for 30 minutes, the solution was cooled by being left at room temperature. Then, the anti-hCG antibody C was added to the gold colloid solution that is adjusted to pH8.9 with a 0.2M potassium carbonate solution, and the solution was shaken for several minutes. Thereafter, a 10% BSA (bovine serum albumin) solution of pH8.9 was added to the solution by such an amount that the concentration thereof finally becomes 1%, and the solution was stirred, thereby preparing antibody-gold colloid complexes (marker antibody). The marker antibody solution was subjected to centrifugation at 4° C. and 20000 G for 50 minutes to isolate the marker antibody, and then the marker antibody was suspended in a washing buffer solution (1% BSA 5% sucrose phosphoric acid solution), and subjected to centrifugation to wash and isolate the marker antibody. The marker antibody was suspended in a washing buffer solution, and filtered with a 0.8 μm filter, and thereafter, adjusted so that the absorbance at 520 nm becomes 150, and then stored at 4° C. The marker antibody solution was set in a solution discharge device, and applied to a position apart from the immobilized line I and the immobilized line II on the dried film to which the immobilization anti-hCG antibody A and the immobilization anti-hCG antibody B are applied so as to have a positional relationship of the marker antibody, the immobilized line I, and the immobilized line II arranged in this order from the liquid sample application start position, and thereafter, the film was subjected to vacuum freeze dry. Thereby, a reaction layer carrier having the reagent immobilization parts and the marker reagent part was obtained.
Next, the reaction layer carrier including the prepared marker reagent was bonded to a substrate 8 comprising a 0.5 mm thick white PET, and a transparent tape was bonded thereto from the marker reagent part 2 to the end part. Thereafter, the substrate 8 was cut into widths of 2.0 mm using laser. After the cutting, a fine space formation member 9 formed by laminating 100 μm thick transparent PET was bonded onto the front end portion where the transparent tape is not bonded, thereby forming a fine space 6 (width 2.0 mm×length 7.0 mm×height 0.3 mm). A 10% potassium chloride solution was previously applied to the space formation member 9, and then the space formation member 9 was quickly frozen by liquid nitrogen and freeze-dried, thereby forming the space formation member which holds the cell contraction agent that is potassium chloride being held in its dry state. Thus, the immunochromatography sensor was manufactured.
hCG solutions of known concentrations were added to human blood to which heparin was added as an anticoagulant, thereby preparing blood having hCG concentrations of 100 U/L, 1000 U/L, and 10000 U/L. The total protein concentration in this blood was set to 7.5 g/dL, and the hematocrit value was adjusted to 20%, 30%, 40%, and 50%.
Further, hCG solutions of known concentrations were added to human blood plasma to prepare blood plasma having hCG concentrations of 100 U/L, 1000 U/L, and 10000 U/L. The total protein concentration was set to 2.5 g/dL, 5 g/dL, 7.5 g/dL, 10 g/dL, and 12.5 g/dL.
Furthermore, hCG solutions of known concentrations were added to human urine to prepare urine having hCG concentrations of 100 U/L, 1000 U/L, and 10000 U/L.
Thus, the respective liquid sample solutions were prepared.
The whole blood containing hCG which was prepared in the step b) was applied by about 5 μL to the sample application part of the immunochromatography sensor, and reflection absorbances at the reagent immobilization parts 3 and 4 were measured by the signal measurement unit 20.
An area of 20.0 mm from the start end to the middle of the channel in which the correlation between the developing speed and the deviation degree was largest in the inspection of the detection section in step d) of the first example was adopted as a detection section, and a liquid sample identification algorithm was derived from the relationship of the developing speeds that vary depending on the respective liquid samples in this detection section.
The developing speeds of the respective liquid samples are shown in
e) Measurement of hCG Concentration in Urine when the Liquid Sample is Identified as Urine
Measurement of the hCG concentration in urine will be described with reference to
Initially, the liquid sample identification algorithm 110 stored in the algorithm holding unit 40 was selected by the algorithm selection unit 80, and the liquid sample was identified as urine according to the liquid sample identification algorithm. Next, the calibration curve for urine stored in the algorithm holding unit 40 was selected by the algorithm selection unit 80, and the hCG concentration in urine was calculated by the arithmetic processing unit 90.
Next, the algorithm selection unit 80 selects any of the correction formulae stored in the algorithm holding unit 40 on the basis of the measurement value of the hCG concentration, and the parameter and the measurement value were substituted in the selected correction formula by the measurement value correction unit 50, whereby the measurement value of the hCG concentration was corrected to obtain an analysis value of the hCG concentration. A flowchart thereof is shown in
f) Correction of Influence Due to Total Protein Concentration when the Liquid Sample is Identified as Blood Plasma
Measurement of the blood plasma hCG concentration will be described with reference to
Initially, the liquid sample identification algorithm 110 stored in the algorithm holding unit 40 was selected by the algorithm selection unit 80, and the liquid sample was identified as blood plasma according to the liquid sample identification algorithm. Next, the calibration curve for blood plasma stored in the algorithm holding unit 40 was selected by the algorithm selection unit 80, and the hCG concentration in blood plasma was calculated by the arithmetic processing unit 90.
Next, the algorithm selection unit 80 selects any of the correction formulae stored in the algorithm holding unit 40 on the basis of the measurement value of the hCG concentration, and the parameter and the measurement value were substituted in the selected correction formula by the measurement value correction unit 50, whereby the measurement value of the hCG concentration was corrected to obtain an analysis value of the hCG concentration. A flowchart thereof is shown in
g) Correction of Influence Due to Hematocrit Value when the Liquid Sample is Identified as Blood
Measurement of the blood plasma hCG concentration will be described with reference to
Initially, the liquid sample identification algorithm 110 stored in the algorithm holding unit 40 was selected by the algorithm selection unit 80, and the liquid sample was identified as whole blood according to the liquid sample identification algorithm. Next, the calibration curve for whole blood stored in the algorithm holding unit 40 was selected by the algorithm selection unit 80, and the hCG concentration in blood was calculated by the arithmetic processing unit 90.
Next, the algorithm selection unit 80 selects any of the correction formulae stored in the algorithm holding unit 40 on the basis of the measurement value of the hCG concentration, and the parameter and the measurement value were substituted in the selected correction formula by the measurement value correction unit 50, whereby the measurement value of the hCG concentration was corrected to obtain an analysis value of the hCG concentration. A flowchart thereof is shown in
The conceptual diagrams shown in
As described above, when the sixth example is used, quantitative measurement using a chromatography specimen can be performed regardless of the kind of the liquid sample, and the calibration curves and the correction formulae according to the characteristics of the respective liquid samples are provided. Therefore, even when any liquid sample is used, the liquid sample is automatically identified, thereby realizing highly precise quantitative measurement.
While in the first to fifth examples a sensor having a marker reagent part and sample immobilization parts provided on the same nitrocellulose film is used, a porous substrate comprising a material different from nitrocellulose such as a nonwoven fabric, on which a marker reagent is disposed, may be provided on a support member. While gold colloid is used as a marker substance constituting a marker reagent, any material may be used so long as some change occurs around a reaction, for example, coloring material, fluorescent material, phosphorescent material, light-emitting material, oxidation-reduction material, enzyme, nucleic acid, or endoplasmic reticulum may be adopted.
Furthermore, while in the first to fifth examples one marker reagent part and plural reagent immobilization parts are adopted, the market reagent part is not necessarily provided in one position, and the device may be constituted by a combination of plural reagent immobilization parts and plural reagents. For example, when plural reagent immobilization parts are provided, a marker reagent part may be provided at the upper stream side of each reagent immobilization part. In this case, although the construction technique in manufacturing is complicated, an arbitrary number of marker reagent parts can be provided in arbitrary positions.
Further, the liquid samples to be measured include, for example, water, aqueous solution, bodily fluids such as urine, blood plasma, blood serum, and saliva, and solutions in which a solid, powder, or gas is dissolved, and the like, and applications of these samples include, for example, blood test, urine test, water examination, fecal examination, soil analysis, food analysis, and the like. Further, while the examples have been described with the C-reactive protein (CRP) as the target substance, the target substance may be antibody, immunoglobulin, hormone, protein and protein derivative such as enzyme and peptide, bacterium, virus, eumycetes, mycoplasma, parasite, infectious materials such as products or components of them, drugs such as curative drug and abused drug, tumor marker, and the like. To be specific, the target substance may be, for example, human chrionic gonadotropin (hCG), luteinizing hormone (LH), thyroid-stimulating hormone, follicular hormone, parathyroid hormone, adrenocorticotropic hormone, estradiol, prostate specific antigen, hepatitis B surface antigen, myoglobin, CRP, cardiac troponin, HbAlc, albumin, and the like. Furthermore, the above-mentioned examples can be executed for environmental analysis such as water examination and soil analysis, food analysis, and the like. Thereby, simple, speedy, highly sensitive and highly efficient measurement can be realized. Further, since anybody can perform measurement anytime and anywhere, it can be utilized as an analysis device for POCT.
An analysis device of the present invention can realize easy, speedy, highly sensitive, and highly efficient measurement when it analyzes and detects a target substance in a liquid sample on the basis of an arbitrary reaction such as an antigen-antibody reaction, and performs quantitation or semi-quantitation thereof. Further, since anybody can perform measurement anytime and anywhere, it is useful as an analysis device for POCT.
Number | Date | Country | Kind |
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2005-205587 | Jul 2005 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2006/314001 | 7/13/2006 | WO | 00 | 1/14/2008 |