High-Density lipoprotein assay device and method

• US 20030224471A1
• Filed: 04/08/2003
• Published: 12/04/2003
• Est. Priority Date: 04/09/2002
• Status: Active Grant

• Current Assignee: Alere San Diego Incorporated (Abbott Laboratories)
• Original Assignee: Cholestech Corporation (Abbott Laboratories)
• Inventors: Shindelman, Jeffrey, Worthy, Thomas E., Bellet, Neal F., Jones, Ronald M., Nugent, Anthony J.
• Granted Patent: US 7,795,038 B2
• Time in Patent Office: Days
• US Class Current: 435/11
• CPC Class Codes: C12Q 1/60 involving cholesterol
• CPC Class Codes: G01N 2800/044 Hyperlipemia or hypolipemia, e.g. dyslipidaemia, obesity
• CPC Class Codes: G01N 33/54388 based on lateral flow
• CPC Class Codes: G01N 33/558 using diffusion or migration of antigen or antibody immunochromatographic test strips G01N33/54387
• CPC Class Codes: G01N 33/92 involving lipids, e.g. cholesterol , lipoproteins, or their receptors steroid hormones G01N33/743
• 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.]
• CPC Class Codes: Y10T 436/255 including use of a solid sorbent, semipermeable membrane, or liquid extraction

Abstract

An assay device and method for measuring the concentration of HDL-associated cholesterol in a blood-fluid sample are described. The assay design prevents interference by reagents used for such removal with the HDL quantification reaction or with other assays carried out on the same sample. If desired, removal of non-HDL lipoproteins and assay of HDL cholesterol can be carried out without interruption of the assay.

Claims

1. An assay device for measuring serum cholesterol associated with high-density lipoproteins (HDL) in a blood fluid sample also containing low density lipoproteins (LDL) or very low density lipoproteins (VLDL), the device comprising:

(i) a plurality of porous elements through which said blood fluid sample can flow in sequence by capillary action and/or gravity, said plurality comprising;

a sample distribution matrix;

an HDL test pad, downstream of said matrix, in which HDL concentration can be assayed; and

, upstream of said HDL test pad, an element containing an immobilized reagent effective to selectively bind and remove non-HDL lipoproteins from the fluid sample; and

(ii) mounting means effective to adjust the device between (a) a sample-distribution position, wherein the HDL test pad is not in fluid communication with the sample distribution matrix, and (b) a test position, wherein said test pad and distribution matrix are in fluid communication with each other.

2. The device of claim 1, wherein the immobilized reagent is immobilized to a first sample collection region within the sample distribution matrix, which region is placed in fluid communication with the HDL test pad when the device is in the test position.

3. The device of claim 1, wherein the immobilized reagent is immobilized to a porous reagent pad located downstream of the distribution matrix and upstream of the HDL test pad, which reagent pad is placed in fluid communication with the HDL test pad when the device is in the test position.

4. The device of claim 3, wherein the reagent pad is attached to the HDL test pad.

5. The device of claim 1, further comprising a reaction bar to which said HDL test pad is attached.

6. The device of claim 5, wherein said mounting means is effective to adjust the relative positions of the reaction bar and cassette body between said sample-distribution position and said test position.

7. The device of claim 1, wherein said mounting means is further effective to (c) transfer the device from said test position to a position in which said HDL test pad is not in fluid communication with said sample distribution matrix.

8. The device of claim 1, wherein said HDL assay pad comprises a biosensor.

9. The device of claim 8, wherein said biosensor is effective to electrochemically measure production of oxygen or hydrogen peroxide which is dependent on HDL-associated cholesterol concentration within said assay pad.

10. The device of claim 1, wherein said reagent pad comprises a porous polymeric membrane.

11. The device of claim 10, wherein said polymeric membrane contains cationic surface groups.

12. The device of claim 1, wherein said reagent pad comprises multiple stacked membranes, at least one of which contains an immobilized reagent effective to bind non-HDL lipoproteins.

13. The device of claim 1, wherein each of said HDL test pad and said reagent pad is a porous polymeric membrane.

14. The device of claim 4, wherein the HDL test pad and reagent pad are laminated together.

15. An assay device for measuring serum cholesterol associated with high-density lipoproteins (HDL) in a blood fluid sample also containing low density lipoproteins (LDL) or very low density lipoproteins (VLDL), the device comprising:

a sample distribution matrix for distributing the blood fluid sample;

a reagent pad containing an immobilized reagent effective to selectively remove non-HDL lipoproteins from the fluid sample; and

a HDL test pad in which HDL concentration can be assayed, in fluid communication with said reagent pad;

wherein said reagent pad may be brought into fluid communication with said sample matrix.

16. The device of claim 15, wherein said immobilized reagent comprises a sulfonated polysaccharide, and said reagent pad comprises a porous polymeric membrane having cationic surface groups.

17. A method of measuring serum cholesterol associated with high-density lipoproteins (HDL) in a blood fluid sample also containing low density lipoproteins (LDL) or very low density lipoproteins (VLDL), comprising

(a) contacting the sample with an absorptive sample distribution matrix,

wherein said sample distribution matrix is one of a plurality of porous elements contained within an assay device, through which said blood fluid sample can flow in sequence by capillary action and/or gravity, said plurality of elements further including:

an HDL test pad, downstream of the sample distribution matrix, in which HDL concentration can be assayed; and

, upstream of said HDL test pad, an element containing an immobilized reagent effective to selectively bind and remove non-HDL lipoproteins from the fluid sample;

(b) contacting said sample with said element containing said immobilized reagent;

(c) placing said matrix in fluid communication with said HDL test pad, whereby said sample is transferred from said element to said HDL test pad; and

(d) determining the content of HDL lipoproteins in said blood fluid sample;

wherein, prior to step (c), said matrix is not in fluid communication with said HDL test pad.

18. The method of claim 17, wherein said element is a porous reagent pad, located downstream of the distribution matrix and upstream of the HDL test pad, which is placed in fluid communication with the HDL test pad in step (c).

19. The method of claim 18, wherein, prior to step (b), said matrix is not in fluid communication with said reagent pad.

20. The method of claim 18, wherein in step (b), upon contacting said matrix with said reagent pad, said reagent pad is in simultaneous fluid communication with the HDL test pad.

21. The method of claim 20, wherein said reagent pad is attached to said HDL test pad.

22. The method of claim 17, wherein said matrix contains said immobilized reagent, such that the contacting of steps (a) and (b) occurs concurrently.

23. The method of claim 17, wherein said immobilized reagent is contained within a sieving matrix upstream of and contacting said matrix, such that the contacting of steps (a) and (b) occurs in reverse order.

24. The method of claim 17, further comprising the step of breaking said fluid communication between the matrix and the test pad, when a desired amount of sample has been transferred.

25. The method of claim 17, wherein said determining comprises electrochemically measuring production of oxygen or hydrogen peroxide which is dependent on HDL-associated cholesterol concentration, by means of a biosensor within said test pad.