Patent Application
20240426765
The present invention refers to an in-vitro diagnostic analyzer comprising an optical detection unit and configured to determine the presence of air bubbles interfering with the optical measurement and to a an automated method of operating the in-vitro diagnostic analyzer in order to determine if the optical measurement of the biological sample is affected by the presence of air.
In medicine, doctor's diagnosis and patient treatment often relies on the measurement of patient sample parameters carried out by in-vitro diagnostic analyzers. It is important that the analyzers perform correctly by providing precise and reliable measurements. Thus, it is a general requirement for in-vitro diagnostic analyzers to implement workflows that ensure analytical performance.
Some in-vitro diagnostic analyzers comprise a fluidic system, comprising detection units, including e.g. optical detection units, comprising e.g. a flow-through cuvette for the optical measurement of a biological sample introduced therein. The analytical workflow typically includes the use of additional fluids, besides samples, which are sequentially introduced in the fluidic system.
Examples of sample parameters that can be determined by optical measurement of a biological sample such as blood include hemoglobin (Hb) and hemoglobin derivatives. In turn, additional sample parameters can be deduced based on the previous measurements such as Oxygen saturation (SO2) and total Hemoglobin (tHb=sum of all Hemoglobins). In order to perform these measurements the blood sample in the cuvette is typically lysed (hemolyzed) by disruption of cellular particles, including erythrocytes containing the hemoglobin, thereby minimizing light scattering otherwise caused by cells.
Some analyzers may comprise a piezo actuator basically consisting of a piezo-ceramics-driven piston, vibrating typically at a frequency of 40-50 kHz, arranged on one side of the cuvette configured to transmit ultrasonic waves through the cuvette. In this process the membranes of the erythrocytes are disrupted through cavitation and the hemoglobin is released.
A problem often encountered with this fluidic setup is that air bubbles of various sizes may occur in the cuvette that can interfere with the optical measurement. In particular, the air bubbles, besides reducing the volume of sample in the optical path, may also cause light scattering and may reduce the lysis performance due to air compression. Moreover the oxygen content in the air bubbles can change the real oxygen content in the sample being measured.
It is against the above background that aspects of the present disclosure provide certain unobvious advantages and advancements over the prior art. In particular, a new in-vitro diagnostic analyzer (IVD) comprising an optical detection unit comprising a cuvette is herein disclosed that with minor hardware and software modifications with respect to known analyzers enables to achieve both efficient lysis of a biological sample in the cuvette as well as to determine if there is air in the cuvette affecting the optical measurement of the sample.
A respective automated method and presenting the same advantages is herein also disclosed.
In particular, the IVD analyzer of the present disclosure comprises an optical detection unit comprising a cuvette for the optical measurement of a biological sample contained therein, a piezo actuator arranged on one side of the cuvette configured to transmit ultrasonic waves through the cuvette, a piezo receiver arranged on the opposite side of the cuvette configured to receive ultrasonic waves transmitted through the cuvette and a controller configured to operate according to either a lysis operating mode or an air-detection operating mode. According to the lysis operating mode the piezo actuator is configured to transmit ultrasonic waves through the cuvette for disrupting cellular particles contained in the biological sample. According to the air-detection operating mode the piezo actuator is configured to transmit ultrasonic waves through the cuvette and the controller is configured to correlate changes in amplitude and/or shifts of phase of the ultrasonic waves received by the piezo receiver relative to reference values with an eventual presence and quantity of air in the cuvette, in order to determine if the optical measurement of the biological sample is affected by the presence of air.
The term “in-vitro diagnostic analyzer” or “IVD analyzer” as used herein refers to an automated or semi-automated analytical apparatus configured to analyze samples in vitro in order to provide information for screening, diagnosis or treatment monitoring purposes. The IVD analyzer can be designed and configured according to the medical area of application, the parameters to be determined and corresponding laboratory workflows. For example, in a point-of-care testing environment, IVD analyzers can vary from handheld devices with low throughput, short turn-around time and limited number of measurable parameters to compact benchtop instruments with higher throughput and higher number of measureable parameters. Such IVD analyzers are designed to detect certain types of parameters, e.g. gases, electrolytes, metabolites, clinical chemistry analytes, immunochemistry analytes, coagulation parameters, hematology parameters, etc. Depending on the parameters of interest, a variety of different analytical methods and different detection technologies can be applied. For example, in the field of blood gas and electrolyte testing, electrochemical measuring principles and/or conductivity measuring principles and/or optical detection methods are typically used. An IVD analyzer typically comprises a plurality of functional units, each dedicated to a specific task and cooperating with each other in order to enable automated sample processing and analysis. Such functional units may include e.g. a sample input interface for receiving a sample, a fluidic system, an analytical measurement unit or detection unit, a fluid-supply unit, and the like. One or more functional units may be integrated into a larger unit or module in order to simplify the operation of the IVD analyzer.
In particular, the IVD analyzer of the present disclosure comprises at least an optical detection unit comprising a cuvette arranged between a light source and a photodetector, typically a spectrophotometer, for the optical measurement of a biological sample contained therein. A “cuvette” is a container or chamber typically comprising two parallel straight and clear walls at a predetermined distance from each other at least in correspondence of the optical path between the light source and the detector, enabling measuring the intensity of light in a part of the spectrum, that is transmitted or emitted by particular substances present in a sample placed therein. The optical detection unit may be embodied as a flow-through optical detection unit comprising a flow-through cuvette or flow-through optical path enabling fluids such as samples and possibly other fluids to flow in and out.
The IVD analyzer may further comprise an additional detection unit comprising a “flow-through sensor path” that is a fluidic conduit comprising one or more sensors that a sample flowing through the sensor path comes in contact with, e.g. arranged sequentially along the path, e.g. a sensor for each different parameter/analyte to be detected, and may be embodied in a replaceable cartridge-like structure comprising a plurality of sensors, possibly distributed across a plurality of sensor paths. In alternative, the IVD analyzer may comprise a plurality of detection units, each having a sensor path comprising a sensor dedicated to one parameter/analyte, and which may also be replaceable or not. A sample may thus flow into the one or more sensor paths and different parameters/analytes may be determined by respective sensors. The term “sensor” is herein generically used to indicate a detector configured to detect sample parameters by generating a correlated signal output that can be quantified and digitized. The sensor can be e.g. a biosensor, a chemical sensor or a physical sensor and is typically a part of a functional unit of an IVD analyzer, e.g. an analytical measurement unit or detection unit. The sensor can be selective or specific with respect to one sample parameter of interest or can be configured to detect and quantify a plurality of different sample parameters of interest. Depending on the type of sensor, a sensor can comprise a plurality of sensory elements. The term “sensory element” therefore refers to a part of a sensor (e.g. to a working electrode, a reference electrode, a counter electrode) that in combination with one or more other sensory elements forms a fully functional sensor. According to an embodiment, the flow-through sensor path comprises any one or more of a pO2 sensor, a pCO2 sensor, a pH sensor, one or more ion selective electrode (ISE) sensors for determining electrolyte values such Na+, K+, Ca2+ and Cl−, one or more metabolite sensors for determining parameters such as lactate and glucose. The sensors may be e.g. respectively based on the amperometric, potentiometric or conductometric principle.
The IVD analyzer may further comprise at least one pump, e.g. a peristaltic pump, syringe pump, membrane pump or any other suitable pump, for transporting e.g. samples from sample containers, wash fluid and possibly other fluids from a fluid-supply unit, or ambient air through the detection unit(s).
In particular, the IVD analyzer of the present disclosure comprises a piezo actuator arranged on one side of the cuvette configured to transmit ultrasonic waves through the cuvette and a piezo receiver arranged on the opposite side of the cuvette configured to receive ultrasonic waves transmitted by the piezo actuator though the cuvette. Ultrasonic waves are sound waves created by vibrations. These vibrations create areas of more and less densely packed particles, when travelling in a medium such as air, liquid or solid. Sound waves travel faster in denser substances because neighboring particles more easily bump into one another. Thus sound waves travel much faster in a liquid than they do in air. In freshwater at room temperature, for example, sound travels about 4.3 times faster than it does in air at the same temperature.
The term “piezo actuator” is herein used to indicate a generator of ultrasonic waves by use of a piezoelectric crystal, typically embodied as a film or thin layer of multiple, tiny, interlocking crystal domains that have positive and negative charges. By applying a voltage the crystal can undergo expansion or contraction. In particular, by applying a modulated voltage a vibration of the crystal can be obtained.
Depending on the design, e.g. material, shape, thickness and vibration mode, e.g. radial mode or thickness mode, the crystal can vibrate in different frequency ranges and have different resonance frequencies.
A piezoelectric crystal can also operate in the opposite way, that is when compressive or tensile mechanical stress is applied to the elements, the crystal generates a proportional voltage and its signal can be used to measure vibration, strain and pressure for example, thus operating as a sensor or detector.
The term “piezo receiver” is herein used to indicate a piezoelectric crystal, that can be structurally similar or even identical to that of the piezo actuator, but that is used as a detector of ultrasonic waves transmitted by the piezo actuator though the cuvette, that is by measuring the voltage generated as a result of the vibration induced on the piezo receiver by the transmitted ultrasonic waves. In particular, by measuring the voltage generated it is possible to determine the wave energy and hence the wave amplitude. This is because wave's energy and wave's amplitude are closely related to each other. The relation between the energy of the wave and the amplitude of the wave is given by the formula E∝A2 where E denotes the wave's energy, and A denotes the wave's amplitude. We can see that the wave's energy is directly proportional to the square of the amplitude of the wave. Thus, if there is a slight change in energy, it results in a squared change in amplitude. When a wave propagates from one medium to another, a part of the wave goes through the new medium and the remaining part is reflected back. Thus changing media causes a decrease in energy, that directly leads towards a change and more precisely a reduction of amplitude.
When a sound wave passes from a liquid, such as a sample contained in the cuvette, into air, eventually also present in the cuvette, a change and in particular a decrease or attenuation of wave amplitude can be observed when compared to the same wave travelling only through the sample filling the cuvette in absence of air bubbles. In particular, it is possible to correlate changes in received wave amplitudes relative to reference values (obtained under the same conditions with the sample filling the cuvette in absence of air bubbles) with the presence and quantity of air in the cuvette, in order to determine if the optical measurement of the biological sample is affected by the presence of air.
Typically, when a wave passes from a medium, e.g. a liquid medium like a sample, into another medium such as air, also a shift of wave phase relative to reference wave phases (observed under the same conditions with the sample filling the cuvette in absence of air bubbles) can be observed and can thus be correlated with the presence and quantity of air in the cuvette.
In general, a change and more specifically attenuations/reductions of wave amplitude and/or shifts of wave phase can be possibly correlated also to different statuses of the sample such as to different levels of hematocrit and/or to lysed or non-lysed sample status and/or to the presence of clots.
According to an embodiment, the piezo actuator and the piezo receiver are ring shaped such as to form an optical window in the middle of the ring for the optical measurement of the biological sample through the cuvette.
The term “sample” refers to a biological material potentially containing one or more analytes of interest and whose detection or analysis, qualitative and/or quantitative measurement, may be associated to a clinical condition. The sample can be derived from any biological source, such as a physiological fluid, including blood, saliva, ocular lens fluid, cerebral spinal fluid, sweat, urine, milk, ascites fluid, mucous, synovial fluid, peritoneal fluid, amniotic fluid, tissue, cells or the like. The test sample can be pretreated prior to use, such as preparing plasma or serum from blood, diluting viscous fluids, lysis or the like; methods of treatment can involve filtration, centrifugation, distillation, concentration, inactivation of interfering components, and the addition of reagents. A sample may be used directly as obtained from the source in some cases or following a pretreatment and/or sample preparation workflow to modify the character of the sample, e.g. after adding an internal standard, after being diluted with another solution or after having being mixed with reagents e.g. to enable carrying out one or more in vitro diagnostic tests, or for enriching (extracting/separating/concentrating) analytes of interest and/or for removing matrix components potentially interfering with the detection of the analyte(s) of interest.
According to one aspect, the sample is blood or a blood derivative such as plasma or serum.
According to certain aspects, analytes of interest are hemoglobin, hemoglobin derivatives such as deoxygenated Hemoglobin (HHb), Oxyemoglobin (O2Hb), Carboxyhemoglobin (COHb), Methemoglobin (MetHb), bilirubin, Urea, Creatinine, typically measured in the optical detection unit. In turn, additional sample parameters can be deduced based on the previous measurements such as Oxygen saturation (SO2=O2Hb/(O2Hb+HHb)) and total Hemoglobin (tHb=sum of all Hemoglobins). Other analytes of interest are gases, such as O2 and CO2, blood electrolytes such as Sodium (Na+), Potassium (K+), Chloride (Cl−), Calcium (Ca++), protons (H+) in relation to pH, metabolites such as Glucose and Lactate, and the like, typically measured in a flow-through sensor path. The list is however not exhaustive.
Samples are typically entered into the fluidic system via a sample input interface, different from the fluid-supply unit, that is another module or component of an in-vitro diagnostic analyzer typically arranged at a position conveniently accessible by an operator and configured to transfer a sample from a sample container, brought up by the operator, into the in-vitro diagnostic analyzer. The sample input interface may e.g. comprise a sample input port comprising an outer input-port side configured for coupling, attaching, connecting, sitting, introducing or plugging-in a sample container, e.g. of the capillary-type or syringe-type, and an inner input-port side coupled to or for coupling to one end of a sample-input conduit, the sample input conduit being fluidically connected or connectable to the detection unit(s).
The term “controller” as used herein may include any physical or virtual processing device and in particular a programmable logic controller running a computer-readable program provided with instructions to perform operations in accordance with an operation plan and in particular in accordance with the method of operating the IVD analyzer in order to determine if the optical measurement of the biological sample is affected by the presence of air, as herein disclosed. This may include a processor, a controller, a central processing unit (CPU), a microprocessor, a microcontroller, a reduced instruction circuit (RISC), an application-specific integrated circuit (ASIC), a logic circuit, or any other circuit or processor configured to execute one or more of the functions/methods described herein. In particular, the controller, among other possible configurations and functions, is configured to correlate changes in amplitude and/or shifts of phase of the ultrasonic waves received by the piezo receiver relative to reference values with an eventual presence and quantity of air in the cuvette, in order to determine if the optical measurement of the biological sample is affected by the presence of air.
In particular, the controller is configured to operate according to either a lysis operating mode or an air-detection operating mode. The term “either” is herein used to indicate that the controller is configured to operate according to both the lysis operation mode and the air-detection operating mode, typically one at a time, although in principle the controller may be configured to operate according to both the lysis operation mode and the air-detection operating mode simultaneously.
A “lysis operation mode” is a mode in which the piezo actuator has the function of transmitting ultrasonic waves through the cuvette in order to disrupt (lyse) cellular particles contained in the biological sample, whereas the piezo receiver is not having any particular function in the lysis operation mode. In this process the membranes of cells contained in the sample, e.g. erythrocytes, are disrupted through cavitation and their content, e.g. hemoglobin, is released.
An “air-detection operating mode” is a mode in which the piezo actuator and the piezo receiver cooperate with each other in order to determine if the optical measurement of the biological sample is affected by the presence of air, thereby exercising jointly a completely different function with respect to the lysis operation mode.
Also, the ultrasonic waves transmitted by the piezo actuator according to the air-detection operating mode may have different amplitude and/or frequency with respect to the ultrasonic waves transmitted according to the lysis operating mode.
According to an embodiment, the amplitude is greater than about 200 V, e.g. about 400-500 V or more according to the lysis operating mode and smaller than about 50 V, e.g. about 10-20 V according to the air-detection operating mode. This is because in order to obtain lysis a higher vibration energy is typically required, whereas in order to detect the presence of air a much lower energy is sufficient.
According to an embodiment, the frequency is smaller than about 60 KHz, e.g. about 40-50 KHz according to the lysis operating mode and greater than about 60 KHz, e.g. about 90-200 KHz according to the air-detection operating mode. In particular, by increasing the frequency and thereby reducing the wavelength of the transmitted ultrasonic wave (the wavelength being inversely proportional to the frequency according to the formula λ=v/f where v is the velocity, λ is the wavelength and f the frequency), the sensitivity to smaller objects such as smaller air bubbles can be increased, given a certain cuvette thickness, i.e. the distance between the cuvette walls, typically in the range of up to a few millimeters.
According to an embodiment, according to the air-detection operating mode, the controller is configured to scan a predetermined resonance frequency range and to correlate changes in a received wave amplitude spectrum relative to reference wave amplitude spectra and/or a shift of a wave phase profile relative to reference wave phase profiles with the presence and quantity of air in the cuvette. In particular, whereas in the lysis operating mode it may be advantageous to set a fixed frequency at or near to the resonance frequency of the piezo actuator in order to maximize the vibrational energy and efficiency, in the air-detection mode it may be advantageous, due to variable conditions, possibly including different air bubble sizes, variable ambient temperature and the like, to sweep the vibrational frequency in a frequency range in order to collect more data and detect changes over a broader spectrum, e.g. by analyzing amplitude spectra and/or wave phase profiles rather than single values.
According to an embodiment, the controller is configured to operate the IVD analyzer according to the air-detection operating mode before and after operation according to the lysis operating mode in order to additionally determine, by comparison, a lysis result obtained during the lysis operating mode.
The present disclosure also refers to an automated method of operating an IVD analyzer comprising an optical detection unit comprising a cuvette for the optical measurement of a biological sample contained therein, a piezo actuator arranged on one side of the cuvette configured to transmit ultrasonic waves through the cuvette, a piezo receiver arranged on the opposite side of the cuvette configured to receive ultrasonic waves transmitted through the cuvette and a controller configured to operate according to either a lysis operating mode or an air-detection operating mode. According to the lysis operating mode the method comprises transmitting ultrasonic waves through the cuvette by the piezo actuator for disrupting cellular particles contained in the biological sample, and wherein according to the air-detection operating mode the method comprises transmitting ultrasonic waves through the cuvette by the piezo actuator and correlating changes in amplitude and/or shifts of phase of the ultrasonic waves received by the piezo receiver relative to reference values with an eventual presence and quantity of air in the cuvette, in order to determine if the optical measurement of the biological sample is affected by the presence of air.
According to an embodiment, the method comprises having the piezo actuator and the piezo receiver ring shaped such as to form an optical window in the middle of the ring for the optical measurement of the biological sample through the cuvette.
According to an embodiment, the method comprises transmitting the ultrasonic waves according to the air-detection operating mode with different amplitude and/or frequency with respect to the ultrasonic waves transmitted according to the lysis operating mode.
According to an embodiment, the amplitude is greater than about 200 V, e.g. about 400-500 V or more according to the lysis operating mode and smaller than about 50 V, e.g. about 10-20 V according to the air-detection operating mode.
According to an embodiment, the frequency is smaller than about 60 KHz, e.g. about 40-50 KHz according to the lysis operating mode and greater than about 60 KHz, e.g. about 90-200 KHz according to the air-detection operating mode.
According to an embodiment, according to the air-detection operating mode, the method comprises scanning a predetermined resonance frequency range and correlating changes in a received wave amplitude relative to reference wave amplitude spectra and/or a shift of a wave phase profile relative to reference wave phase profiles with the presence and quantity of air in the cuvette.
According to an embodiment, the method comprises performing the optical measurement of the biological sample if it is determined that the optical measurement is unaffected by the presence of air.
According to an embodiment, the method comprises operating the IVD analyzer according to the air-detection operating mode before and after operating the IVD analyzer according to the lysis operating mode in order to additionally determine by comparison a lysis result obtained during the lysis operating mode.
Other and further objects, features and advantages will appear from the following description of exemplary aspects and accompanying drawings, which serve to explain the principles more in detail.
Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements whereas other elements may have been left out or represented in a reduced number in order to enhance clarity and improve understanding of the aspects of the present disclosure.
The IVD analyzer 200 further comprises a pump 240, such as a peristaltic pump, located downstream of the of the fluidic system 210, and a fluid-supply unit 220 comprising a plurality of fluids 221, 222, 223, and a waste container 224 where fluids circulated through the fluidic system 210 may be disposed of, by the action of the pump 240. The IVD analyzer 200 further comprises a fluid-selection valve 230 for selecting between the fluids 221, 222, 223 and/or air 232.
The IVD analyzer 200 further comprises a sample input interface 201, comprising a sample input port 10 comprising an outer input-port side 11 configured for plugging-in an open end of a sample container 1 and an inner input-port side 12. The sample container 1 is in this example a capillary-like sample container. The sample input interface 201 further comprises an aspiration needle 30 comprising an upstream end 31 and a downstream end 32. The downstream end 32 of the aspiration needle 30 is fluidically connected to the fluidic system 210 via fluidic line 219 whereas the upstream end 31 is configured to alternately couple to the inner input-port side 12 in order to aspirate a sample 2 from the sample container 1 plugged in the outer input-port side 11 and to a fluid-supply unit port 40 fluidically connected to a common outlet port 231 of the fluid-selection valve 230 via a further conduit 219′. The fluidic line 219 may be however directly connected to the outlet port 231 of the fluid-selection valve 230, whereas samples may be introduced via a different fluidic line separately connected to the fluid-selection valve 230, for example.
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In this example, the method also comprises having the piezo actuator 218 and the piezo receiver 218′ ring shaped such as to form an optical window 218″ in the middle of the ring for the optical measurement of the biological sample through the cuvette 214. In this example, the method also comprises transmitting the ultrasonic waves 254 according to the air-detection operating mode (AD) with different amplitude and/or frequency with respect to the ultrasonic waves 254′ transmitted according to the lysis operating mode (L). The method further comprises performing the optical measurement of the biological sample 2′ if it is determined that the optical measurement is unaffected by the presence of air. The method also comprises operating the IVD analyzer according to the air-detection operating mode (AD) before and after operating the IVD analyzer according to the lysis operating mode (L) in order to additionally determine by comparison a lysis result obtained during the lysis operating mode (L).
Modifications and variations of the disclosed aspects are also certainly possible in light of the above description. It is therefore to be understood, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically devised in the above examples.
Particularly, it is to be understood that at least some of the drawings or parts are only schematic and provided as way of example only. Also the relationship between elements may be other than the one shown, whereas parts not relevant for the purpose of this disclosure have been omitted.
Also, reference throughout the preceding specification to “one aspect”, “an aspect”, “one example” or “an example”, “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the aspect or example or embodiment is included in at least one aspect, example or embodiment. Thus, appearances of the phrases “in one aspect”, “in one aspect”, “one example” or “an example”, “one embodiment” or “an embodiment”, in various places throughout this specification are not necessarily all referring to the same aspect or example or embodiment.
Furthermore, the particular features, structures, or characteristics may be combined in any suitable combinations and/or sub-combinations in one or more aspects or examples or embodiments.
| Number | Date | Country | Kind |
|---|---|---|---|
| 23181338.7 | Jun 2023 | EP | regional |
| 23190576.1 | Aug 2023 | EP | regional |
