Method for verifying fitness of an analysis element

• US 7,736,904 B2
• Filed: 01/25/2008
• Issued: 06/15/2010
• Est. Priority Date: 09/01/2000
• Status: Expired due to Fees

• Current Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Original Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Inventors: Albrecht, Gertrud, Loch-Leroux, Dieter, Gaa, Otto
• Primary Examiner(s): Gakh; Yelena G
• Application Number:
  US12/020,259
• Publication Number:
  US 20080138906A1
• Time in Patent Office: 872 Days
• Field of Search: None
• US Class Current: 436/169
• CPC Class Codes: G01N 33/52 Use of compounds or compositions for colorimetric, spectrophotometric or fluorometric investigation, e.g. use of reagent paper and including single- and multilayer analytical elements immunological elements G01N33/54386; involving labelled immunochemicals G01N33/58; for haemoglobin or occult blood G01N33/72
• CPC Class Codes: Y10T 436/10 Composition for standardization, calibration, simulation, stabilization, preparation or preservation; processes of use in preparation for chemical testing
• CPC Class Codes: Y10T 436/11 Automated chemical analysis

Abstract

The present invention pertains to a method for verifying usability of a test element on the basis of the relation of at least one control parameter measurable from the blank test field of a test element to a standard value for the at least one control parameter. In one embodiment, the method comprises determining the deviation between a first ratio calculated from a blank-field reference value measured for the control parameter and a first standard value, and a second ratio calculated from a blank-field control value and the first standard value, and rejecting a test element if the deviation is not within a predetermined tolerance range for the deviation.

Claims

1. A method for verifying the usability of a test element provided for use with a corresponding evaluation unit for analysis of a liquid sample, the method comprising the steps of:

a) determining a first standard value (W1) for at least one control parameter measured from a standard reference presented to the evaluation unit, the standard reference providing a standardized reference value (W1) for the at least one control parameter;

b) providing a first test element comprising a first test field to the evaluation device and determining a blank-field reference value (L1) for the at least one control parameter from the first test field);

c) calculating a first ratio (Q1=L1/W1 or W1/L1) from the reference value (L1) and the first standard value (W1);

d) providing a second test element comprising a second test field to the evaluation device and determining a blank-field control value (L2) for the at least one control parameter from the second test field;

e) calculating a second ratio (Q2=L2/W1 or W1/L2) from the control value (L2) and the first standard value (W1);

f) determining a deviation (Δ

) between the second ratio (Q2=L2/W1 or W1/L2) and the first ratio (Q1=L1/W1 or W1/L1); and

g) rejecting the second test element if the deviation (Δ

) is not within a pre-determined tolerance range for the deviation (Δ

).

2. The method according to claim 1, wherein determining the deviation (Δ

) comprises calculating a relative difference (δ

) between the second ratio (Q2=L2/W1 or W1/L2) and the first ratio (Q1=L1/W1 or W1/L1).

3. The method according to claim 1, wherein determining the deviation (Δ

) comprises calculating an absolute difference (Q1−

Q2 or Q2−

Q1) between the second ratio (Q2=L2/W1 or W1/L2) and the first ratio (Q1=L1/W1 or W1/L1).

4. The method according to claim 1, wherein the rejecting step comprises rejecting the second analysis element if the second ratio (Q2=L2/W1 or W1/L2) is smaller than the first ratio (Q1=L1/W1 or W1/L1) by at least a pre-determined percentage.

5. The method according of claim 1, wherein the rejecting step comprises rejecting the second analysis element if the second ratio (Q2=L2/W1 or W1/L2) is smaller than the first ratio (Q1=L1/W1 or W1/L1) by at least a pre-determined absolute difference value (Q1−

Q2 or Q2−

Q1).

6. The method according to claim 1, wherein the at least one control parameter is an optically measurable value.

7. The method according to claim 6, wherein the optically measurable value comprises a remission value.

8. The method according to claim 1, wherein the first pre-determined tolerance range for the deviation (Δ

) is determined with respect to a batch of test elements from which the first and second test elements are provided.

9. The method according to claim 1, further comprising calculating a new ratio from the control value (L2) and the first standard value (W1).

10. The method according to claim 1, wherein the first test element and the second test element are provided after being removed from a container configured for substantially preventing deterioration of the first test element and the second test element.

11. The method according to claim 10, wherein the first test element is provided to the evaluation device before the second test element.

12. The method according to claim 1, further comprising the steps of:

h) re-assigning the second ratio (Q2=L2/W1 or W1/L2) as a new first ratio (Q1=L1/W1 or W1/L1);

i) providing a third test element having a third test field to the evaluation device and determining a new blank-field control value (L2) for the at least one control parameter from the third test field;

j) calculating a third ratio (Q2=W1/L2 or L2/W1) from the new control value (L2) and the first standard value (W1);

k) determining a deviation (Δ

) between the third ratio (Q2=W1/L2 or L2/W1) and the new first ratio (Q1=L1/W1 or W1/L1); and

l) rejecting the third test element if the deviation (Δ

) determined from step (k) is not within the pre-determined tolerance range for the deviation (Δ

).

13. The method according to claim 12, further comprising the steps of determining whether the deviation (Δ

) determined from step (f) exceeds a pre-determined limit value (δ

), wherein step (h) is not performed if the determination shows the deviation determined from step (f) does exceed the pre-determined limit value (δ

), and wherein if step (h) is not performed then step (k) comprises determining a deviation (Δ

) between the third ratio (Q2=W1/L2 or L2/W1) and the first ratio (Q1=L1/W1 or W1/L1).

14. The method according to claim 13, wherein the pre-determined limit value (δ

) is determined with respect to a batch of test elements from which the first, second and third test elements are provided.