DETECTION OF FALSE RESULTS IN ASSAYS

• US 20100240073A1
• Filed: 03/23/2009
• Published: 09/23/2010
• Est. Priority Date: 03/23/2009
• Status: Active Grant

• Current Assignee: Siemens Healthcare Diagnostics Incorporated (Siemens AG)
• Original Assignee: Siemens Healthcare Diagnostics Incorporated (Siemens AG)
• Inventors: Wei, Tie Quan
• Granted Patent: US 8,084,223 B2
• Time in Patent Office: Days
• US Class Current: 435/7.250
• CPC Class Codes: G01N 33/9493 Immunosupressants
• CPC Class Codes: Y10T 436/106664 Blood serum or blood plasma standard or control
• CPC Class Codes: Y10T 436/107497 Preparation composition [e.g., lysing or precipitation, etc.]
• CPC Class Codes: Y10T 436/25125 Digestion or removing interfering materials
• CPC Class Codes: Y10T 436/25375 Liberation or purification of sample or separation of material from a sample [e.g., filtering, centrifuging, etc.]

Abstract

Methods and reagents are disclosed for detecting a false result in an assay for determining a concentration of an analyte in a whole blood sample suspected of containing the analyte. The method comprises determining by means of the assay a concentration of the analyte utilizing a hemolyzed portion of the blood sample to obtain concentration value 1 and determining by means of the assay a concentration of the analyte utilizing a non-hemolyzed portion of the blood sample and multiplying the concentration times a hematocrit factor to obtain concentration value 2. A ratio of concentration value 1 divided by concentration value 2 is determined and is compared to a predetermined ratio of known reliability. If the ratio is less than the predetermined ratio, a false result is indicated.

Claims

1. A method for detecting a false result in an assay for determining a concentration of an analyte in a whole blood sample suspected of containing the analyte, the method comprising:

(a) determining by means of the assay a concentration of the analyte utilizing a hemolyzed portion of the blood sample to obtain concentration value 1,

(b) determining by means of the assay a concentration of the analyte utilizing a non-hemolyzed portion of the blood sample and multiplying the concentration times a hematocrit factor to obtain concentration value 2,

(c) determining a ratio of concentration value 1 divided by concentration value 2, and

(d) comparing the ratio from (c) to a predetermined ratio of known reliability wherein, if the ratio is less than the predetermined ratio, a false result is indicated.

2. The method of claim 1 wherein the predetermined ratio of known reliability is determined by a method that is independent of factors that produce a false result in the assay and wherein the predetermined ratio is a ratio of a concentration of the analyte in a hemolyzed portion of a whole blood sample that contains the analyte divided by a concentration of analyte in a non-hemolyzed portion of the whole blood sample.

3. The method according to claim 1 wherein the hematocrit factor is the following equation:

1/(1-hematocrit % in decimal form).

4. The method according to claim 1 wherein the assay comprises:

(i) adding to a medium comprising the blood sample of step (a) or step (b) reagents for determining the concentration of the analyte in the blood sample wherein the reagents comprise at least one antibody for the analyte, and

(ii) measuring an amount of a complex comprising the analyte and the antibody for the analyte and relating the amount of the complex to the concentration of the analyte in the blood sample.

5. The method according to claim 4 wherein the reagents in step (i) further comprise an analog of the analyte and at least one the antibody for the analyte or the analog comprises a label.

6. The method according to claim 4 wherein in step (i) a second antibody is added to the medium wherein the second antibody binds to a complex of the analyte and the antibody for the analyte.

7. The method according to claim 6 wherein at least one of the antibodies for the analyte and the second antibody comprises a label.

8. The method according to claim 4 wherein one of the reagents comprises a label.

9. The method according to claim 4 wherein one of the reagents comprises a particle.

10. The method according to claim 4 wherein one of the reagents comprises an enzyme label and one of the reagent comprises a magnetic particle.

11. A method for detecting a false result in an assay for determining a concentration of an analyte in a whole blood sample suspected of containing the analyte, the method comprising:

(a) determining by means of the assay a concentration of the analyte utilizing a hemolyzed portion of the blood sample to obtain concentration value 1,

(b) determining by means of the assay a concentration of the analyte utilizing a non-hemolyzed portion of the blood sample and multiplying the concentration times a hematocrit factor to obtain concentration value 2 wherein the hematocrit factor is the following equation;

1/(1-hematocrit % in decimal form), wherein the assay comprises;

(i) adding to a medium comprising the blood sample of step (a) or step (b) reagents for determining the concentration of the analyte in the blood sample wherein the reagents comprise at least one antibody for the analyte, and

(ii) measuring an amount of a complex comprising the analyte and the antibody for the analyte and relating the amount of the complex to the concentration of the analyte in the blood sample,

(c) determining a ratio of concentration value 1 divided by concentration value 2, and

(d) comparing the ratio from (c) to a predetermined ratio of known reliability wherein, if the ratio is less than the predetermined ratio, a false result is indicated and wherein the predetermined ratio of known reliability is determined by a method that is independent of factors that produce a false result in the assay and wherein the predetermined ratio is a ratio of a concentration of the analyte in a hemolyzed portion of a whole blood sample that contains the analyte divided by a concentration of analyte in a non-hemolyzed portion of the whole blood sample.

12. The method according to claim 11 wherein the analyte is an erythrocytophilic drug.

13. The method according to claim 11 wherein the analyte is an immunosuppressant drug.

14. The method according to claim 11 wherein the assay method is a heterogeneous assay method.

15. The method according to claim 11 wherein the reagents in step (i) further comprise an analog of the analyte and at least one the antibody for the analyte or the analog comprises a label.

16. The method according to claim 11 wherein in step (i) a second antibody is added to the medium wherein the second antibody binds to a complex of the analyte and the antibody for the analyte.

17. The method according to claim 16 wherein at least one of the antibodies for the analyte and the second antibody comprises a label.

18. The method according to claim 11 wherein one of the reagents comprises a label.

19. The method according to claim 11 wherein one of the reagents comprises a particle.

20. The method according to claim 11 wherein one of the reagents comprises an enzyme label and one of the reagents comprises a magnetic particle.