Coagulation or lysis assays by measuring impedance
First Claim
1. A device for performing a coagulation or lysis assay of a sample, the device comprising:
- a housing having an exterior surface and defining an interior area;
means for receiving the sample through the housing into the interior area;
a non-porous substrate positioned within the interior area for receiving the sample;
a reagent for accelerating the coagulation of the sample in the housing and contact with the sample;
means for measuring the impedance of the sample and generating a signal which correlates to a curve of the coagulation or lysis assay; and
processing means being positioned within the interior area and connected to the measuring means for receiving and converting the signal into an output external to the housing corresponding to the coagulation or lysis assay using assay calibration information stored in the device.
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Abstract
The present invention provides a single-use electronic device and test card for use therein which performs a coagulation or lysis assay of a blood or plasma sample. The device includes a housing having an exterior surface and defining an interior area and means for receiving the sample through the housing into the interior space. A non-porous substrate is positioned within the interior space for receiving the sample thereon. Preferably, a reagent accelerates the coagulation of the sample and is positioned on the substrate and in contact with the sample. An electroactive species is added to the sample. The device also measures the impedance of the sample and generating an electrical signal which correlates to a curve of the coagulation/lysis assay. Optionally, the electrical signal is received and converted into a digital output corresponding to the coagulation/lysis assay using assay calibration information stored therein. The digital output can be displayed external to the housing. A method of determining the coagulation or lysis of a sample provides for measuring the impedance of the sample and generating an electrical signal which correlates to a curve of the coagulation/lysis assay.
78 Citations
38 Claims
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1. A device for performing a coagulation or lysis assay of a sample, the device comprising:
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a housing having an exterior surface and defining an interior area;
means for receiving the sample through the housing into the interior area;
a non-porous substrate positioned within the interior area for receiving the sample;
a reagent for accelerating the coagulation of the sample in the housing and contact with the sample;
means for measuring the impedance of the sample and generating a signal which correlates to a curve of the coagulation or lysis assay; and
processing means being positioned within the interior area and connected to the measuring means for receiving and converting the signal into an output external to the housing corresponding to the coagulation or lysis assay using assay calibration information stored in the device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
means for generating a signal of predetermined frequency, the generating means being positioned within the interior area;
a plurality of electrodes being positioned on the substrate and contacting the sample, the electrodes connecting to the generating means for passing the signal into the sample, the electrodes generating an electrical signal corresponding to the impedance of the sample.
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4. The device of claim 3 wherein the electrodes generate an electrical signal corresponding to the electrolytic conductance of the sample.
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5. The device of claim 3 wherein the electrodes generate an electrical signal corresponding to the conductivity/resistivity of the sample.
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6. The device of claim 1 wherein the device further includes a heater being positioned within the interior area and in thermal contact with the substrate so that the substrate can be warmed to a pre-determined temperature upon receiving the sample.
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7. The device of claim 1 wherein the processing means further calibrates the signal to a reference standard using the stored assay calibration information.
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8. The device of claim 1 wherein the assay calibration information stored in the device determines results for at least one of assays selected from the group consisting of a Prothrombin Time, an Activated Clotting Time, an Activated Partial Thromboplastin Time, platelet aggregation, and fibrinogen.
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9. The device of claim 1 wherein the measuring means includes applying a potential to the sample.
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10. The device of claim 1 wherein the sample is selected from a group consisting of whole blood and plasma.
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11. The device of claim 1 wherein the sample is retained in a particular position on the substrate.
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12. The device of claim 1 wherein the sample is retained in continuous, direct contact with the measuring means.
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13. A test card for a device determining a coagulation or lysis assay of a sample, the test card comprising:
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a non-porous substrate defining a surface for receiving the sample; and
means for measuring the impedance of the sample and generating a signal which correlates to a curve of the coagulation or lysis assay. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A method of determining the coagulation or lysis of a sample, the steps of the method comprising:
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accelerating coagulation of the sample by chemically reacting the sample with at least one reagent to produce a detectable change in the impedance of the sample which correlates with a state of coagulation or lysis of the sample;
measuring the impedance of the sample and generating a signal which correlates to a curve of the coagulation or lysis; and
processing the signal into an output corresponding to the coagulation or lysis using assay calibration information. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33)
generating a signal of predetermined frequency;
contacting a plurality of electrodes with the sample;
passing the signal through the electrodes into the sample; and
generating an electrical signal with the electrodes corresponding to the impedance of the sample.
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27. The method of claim 26 wherein the method includes the step of calibrating the electrical signal to a reference standard using the assay calibration information to determine results for at least one of assays selected from the group consisting of a Prothrombin Time, an Activated Clotting Time, an Activated Partial Thromboplastin Time, platelet aggregation, and fibrinogen.
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28. The method of claim 24 wherein the measuring step includes measuring the electrolytic conductance of the sample.
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29. The method of claim 24 wherein the measuring step includes measuring the conductivity/resistivity of the sample.
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30. The method of claim 24 wherein the method includes the step of warming the sample to a pre-determined temperature prior to the measuring step.
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31. The method of claim 24 wherein the measuring step includes applying a potential to the sample.
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32. The method of claim 24 wherein the sample is selected from a group consisting of whole blood and plasma.
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33. The method of claim 24 wherein the method includes the step of retaining the sample stationary within a detection area while performing the measuring step.
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34. A method of determining the coagulation or lysis of a blood sample, the steps of the method comprising:
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applying a potential to the blood sample to produce a detectable change in the impedance of the blood sample which correlates with a state of coagulation or lysis of the sample;
determining a rate of change of impedance as the coagulation or lysis of the blood sample proceeds; and
determining the time of coagulation or lysis from the rate of the impedance change by measure a minimum or maximum in the rate of impedance change using assay calibration information. - View Dependent Claims (35, 36, 37, 38)
accelerating coagulation of the blood sample by chemically reacting the blood sample with at least one reagent on a substrate to produce a detectable change in the impedance of the blood sample which correlates with a state of coagulation or lysis of the blood sample.
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36. The method of claim 34 wherein the steps of the method include:
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measuring the impedance of the blood sample and generating an electrical signal which correlates to a curve of the coagulation or lysis by continuously contacting a plurality of electrodes directly with the blood sample and passing a signal of predetermined frequency through the electrodes into the blood sample to generate an electrical signal; and
processing the electrical signal into an output means corresponding to the coagulation or lysis using assay calibration information.
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37. The method of claim 36 wherein the method includes the step of visually displaying a digital output.
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38. The method of claim 34 wherein the method includes using assay calibration information to determine results for at least one of assays selected from the group consisting of a Prothrombin Time, an Activated Clotting Time, an Activated Partial Thromboplastin Time, platelet aggregation, and fibrinogen.
Specification