AUTOMATED METHOD AND APPARATUS FOR DETECTING ERRONEOUS SAMPLE COLLECTION IN CLINICAL ASSAYS

• US 20090173641A1
• Filed: 12/19/2008
• Published: 07/09/2009
• Est. Priority Date: 12/20/2007
• Status: Active Grant

• Current Assignee: Abbott Point Of Care Incorporated (Abbott Laboratories)
• Original Assignee: Abbott Point Of Care Incorporated (Abbott Laboratories)
• Inventors: BROUWER, ERIC, ZELIN, MICHAEL P., Tirinato, Jody Ann
• Granted Patent: US 8,265,904 B2
• Time in Patent Office: Days
• US Class Current: 205/777.500
• CPC Class Codes: G01N 35/00603 Reinspection of samples
• CPC Class Codes: Y10T 436/115831 Condition or time responsive
• CPC Class Codes: Y10T 436/2525 Stabilizing or preserving

Abstract

A method for identifying biological samples that are collected using the wrong anticoagulant for subsequent analytical testing. The method also provides for identification of certain analytical test results that are substantially or partly adversely affected.

Claims

1. An automatic method for determining that a collection device with an anticoagulant was incorrectly used to collect a blood sample for analysis of analyte species in a sample where the correct collection device for the sample omits a selected anticoagulant, the method comprising;

(a) adding a sample from a collection device to an analyzer instrument having means for analyzing species that include a monovalent ion and divalent cation and at least one other analyte;

(b) determining the concentration of monovalent ion, divalent cation and one or more other analyte in said sample;

(c) comparing the monovalent ion concentration to a predetermined upper threshold value and the divalent cation concentration to a predetermined lower threshold value, and where both said threshold concentration values are surpassed said analyzer instrument flags or suppresses concentration values for the monovalent ion, divalent cation and one or more of the other analyte species in said sample, and thereby

(d) reporting by said analyzer that the sample was collected with the wrong anticoagulant.

2. The method of claim 1, wherein the selected anticoagulant is selected from the group consisting of:

K₂EDTA, K₃EDTA, and Na₂EDTA, oxalic acid and salts thereof, ethylene glycol tetra acetic acid (EGTA) and salts thereof, citric acid and salts thereof, fluorides, non-balanced heparins, and combinations thereof.

3. The method of claim 1, wherein the correct collection device contains no anticoagulant or lithium heparin.

4. The method of claim 1, wherein the divalent cation is selected from the group calcium and magnesium.

5. The method of claim 1, wherein the monovalent ion is selected from the group consisting of potassium and sodium.

6. The method of claim 1, wherein said one or more other analyte species is selected from the group consisting of:

calcium, magnesium, potassium sodium, hydrogen, chloride, bicarbonate, ammonium, lithium, pH, pCO₂, pO₂, glucose, creatinine, lactate, blood urea nitrogen, and hematocrit, hemoglobin, O₂ saturation, total CO₂ PT/INR, ACT, APTT, BNP and CRP.

7. The method of claim 1, wherein the divalent cation is calcium and the threshold is about 0.25 mM.

8. The method of claim 1, wherein the divalent cation is calcium and the threshold is a selected value in the range of about 0.3 mM to about 0.001 mM.

9. The method of claim 1, wherein the monovalent ion is potassium and the threshold is about 9 mM.

10. The method of claim 1, wherein the monovalent ion is potassium and the threshold is a selected value in the range of about 8 mM to about 20 mM.

11. The method of claim 1, wherein the divalent cation is magnesium and the threshold is about 0.2 mM.

12. The method of claim 1, wherein the monovalent ion is sodium and the threshold is about 160 mM.

13. The method of claim 1, wherein a second divalent cation concentration is determined and flagging or suppression of results requires both first and second divalent cation concentrations surpass a preselected threshold value for each.

14. The method of claim 1, wherein a second monovalent ion concentration is determined and flagging or suppression of results requires both first and second monovalent ion concentrations surpass a preselected threshold value for each.

15. The method of claim 1, wherein determination of the monovalent ion, the divalent cation and the other analyte species concentrations are determined electrochemically.

16. The method of claim 1, wherein determination of the divalent cation concentration is by a calcium ion-selective electrode.

17. The method of claim 1, wherein determination of the monovalent ion concentration is by a potassium ion-selective electrode.

18. The method of claim 1, wherein determination of the at least one other analyte species concentration is by a sensor selected from the group consisting of:

ion-selective electrode, optode, flame photometer, ion-sensitive dye, an ion-dependent enzyme assay, an enzyme assay, a potentiometric sensor, an amperometric sensor and a conductimetric sensor.

19. The method of claim 1, wherein determination of the divalent cation concentration is by a sensor selected from the group consisting of:

ion-selective electrode, potentiometric sensor, optode, flame photometer, ion-sensitive dye and divalent cation-dependent enzyme assay.

20. The method of claim 1 wherein determination of the monovalent ion concentration is by a sensor selected from the group consisting of:

ion-selective electrode, potentiometric sensor, optode, flame photometer, ion-sensitive dye and ion-dependent enzyme assay.

21. The method of claim 1 wherein the analyzer instrument comprises a laboratory analyzer with one or more reusable sensors comprising:

a sensor for a divalent cation, a sensor for a monovalent ion and at least one other analyte species sensor.

22. The method of claim 1, wherein the analyzer instrument comprises an analyzer having one or more reusable sensors comprising:

a sensor for a divalent cation, a sensor for a monovalent ion and at least one other analyte species sensor.

23. The method of claim 1, wherein the analyzer instrument comprises an analyzer used in combination with a single-use test cartridge, and having one or more sensors including a sensor for a divalent cation, a sensor for a monovalent ion and at least one other analyte species sensor.

24. The method of claim 1, wherein the reporting is by means of a displayed message on the screen of the analyzer, a printed message, an audio message, or transmission of information to another location.

25. The method of claim 1, wherein the collection device is a tube with a stopper sealing the entry to the tube and where the interior of the tube is under a partial vacuum.

26. The method of claim 1, wherein the collection device is selected from the group consisting of:

a collection tube, evacuated tube, syringe and capillary tube.

27. The method of claim 1, wherein the sample is selected from the group consisting of:

blood, plasma, serum and diluted and amended samples thereof.

28. The method of claim 1, performed at a location selected from the group consisting of:

bedside testing, emergency department, operating room, physician'"'"'s office, clinic, blood bank, laboratory, nursing home, remote testing, and mobile testing, e.g., in an ambulance.

29. The method of claim 1, wherein the sample is collected and tested using the analyzer instrument at a point-of-care location.

30. An automatic method for determining that a collection device with an anticoagulant was incorrectly used to collect a blood sample for analysis of analyte species in a sample where the correct collection device for the sample omits a selected anticoagulant, the method comprising;

(a) adding a sample from a collection device to an analyzer instrument having means for analyzing species that include a divalent cation and at least one other analyte,

(b) determining the concentration of a divalent cation and one or more other analyte in said sample,

(c) comparing the divalent cation concentration to a predetermined lower threshold value, and where said threshold concentration value is surpassed said analyzer instrument flags or suppresses concentration values for the divalent cation and one or more of the other analyte species in said sample, and

(d) said analyzer reports that the sample was collected with the wrong anticoagulant.

31. The method of claim 30, wherein the divalent cation is calcium.

32. The method of claim 30, wherein said one or more other analyte species is selected from the group consisting of:

magnesium, potassium sodium, hydrogen, chloride, bicarbonate, ammonium, lithium, pH, pCO₂, pO₂, glucose, creatinine, lactate, blood urea nitrogen, and hematocrit.

33. The method of claim 30, wherein the divalent cation is calcium and the threshold is a selected value in the range of about 0.3 mM to about 0.001 mM.

34. The method of claim 30, wherein the selected anticoagulant is selected from the group consisting of:

K₂EDTA, K₃EDTA, and Na₂EDTA, oxalic acid and salts thereof, ethylene glycol tetra acetic acid (EGTA) and salts thereof, citric acid and salts thereof, fluorides, non-balanced heparins, and combinations thereof.

35. A method of identifying the erroneous collection of a blood sample for the measurement of one or more ionic species in a collection device containing a cationic salt of a calcium binding agent, the method comprising:

taking a blood sample from a collection device;

determining the cation concentration in the sample with respect to an upper threshold value;

determining the calcium ion concentration in the sample with respect to a lower threshold value;

flagging or suppressing the reporting of the cation, calcium and at least one other measured ionic species in said blood sample when both the cation concentration is above the upper threshold and the calcium concentration is below the lower threshold; and

reporting the type of collection device is inappropriate for collection of a blood sample for the measurement of one or more other selected ionic species.

36. The method of claim 35, wherein the calcium binding agent is selected from the group consisting of:

EDTA, EGTA, oxalate, citrate and fluoride.

37. The method of claim 35, wherein the cation is selected from the group consisting of:

sodium and potassium.

38. The method of claim 35, wherein the cation is sodium and the threshold is about 160 mM.

39. The method of claim 35, wherein the cation is potassium and the threshold is about 9 mM.

40. The method of claim 35, wherein the calcium threshold ranges from about 0.3 mM to 0.001 mM.

41. The method of claim 35, wherein the at least one other measured ionic species is selected from the group consisting of:

magnesium, chloride, bicarbonate, potassium, sodium, lithium, ammonium and hydrogen ions.

42. A method of identifying erroneous collection of a biological sample for the measurement of a first species, in a collection device containing a reagent incompatible with the reliable measurement of said first species, said method comprising:

taking a sample from a collection device;

determining the concentration of a second species in the sample with respect to a threshold value;

flagging or suppressing the reporting of a measured concentration of said first and second species where the concentration of the second species is beyond said threshold value; and

reporting the type of collection device is suspected of being inappropriate for collection of a sample for the measurement of said first and second species.

43. The method of claim 42, wherein the biological sample is selected from the group consisting of:

blood, plasma, serum and diluted and amended samples thereof.

44. The method of claim 42, wherein said first species is one of a plurality of species in said sample reported as being collected in an inappropriate collection device.

45. The method of claim 42, wherein said second species is one of a plurality of species for which a concentration is determined in said sample with respect to a threshold value and reported as being collected in an inappropriate collection device.

46. A method of identifying erroneous collection of a biological sample for the measurement of at least one species, in a collection device containing a reagent incompatible with the reliable measurement of said at least one species, the method comprising:

taking a sample from a collection device;

determining the concentration of a plurality of other species in the sample with respect to a threshold value for each of said species;

flagging or suppressing the reporting of a measured concentration of said plurality of species and the at least one species where the concentration of each of said plurality of species is beyond said threshold value; and

reporting the type of collection device is suspected of being inappropriate for collection of a sample for the measurement of said at least one species and said plurality of species.

47. An automatic method for determining that a collection device was incorrectly used to collect a blood sample for analysis of ionic species, the method comprising:

adding a sample from a collection device to an analyzer instrument having means for analyzing ionic species that includes a divalent cation;

determining the concentration of the divalent cation and one or more other ionic species in said sample;

comparing the divalent cation concentration to a predetermined threshold value, and wherein said threshold concentration value is surpassed said analyzer instrument reporting concentration values for the divalent cation and one or more other ionic species in said sample should not be used; and

reporting by said analyzer that the sample was collected with the wrong anticoagulant.

48. The method of claim 47, wherein the incorrectly used collection device contains EDTA and an appropriate collection device omits EDTA.

49. An automatic analyte testing method for distinguishing blood samples incorrectly collected with the wrong anticoagulant from samples collected using the correct anticoagulant;

the method comprising;

(a) introducing a collected sample into an analyzer instrument having means for determining the concentration of at least two analytes in a sample;

(b) determining the concentration of a first analyte and one or more other analyte in said sample;

(c) comparing the first analyte concentration to a predetermined threshold value;

(d) reporting by said analyzer instrument, concentration values for the first analyte and one or more other analytes in said sample where the threshold concentration value is not surpassed, and

(e) reporting by said analyzer instrument, that concentration values for the first analyte and one or more other analytes in said sample should not be used, and reporting that the sample was collected with the wrong anticoagulant where said threshold concentration value is surpassed.