High-density lipoprotein assay device and method
An assay device and method for measuring the concentration of HDL-associated cholesterol in a blood-fluid sample are described. The assay design is such that removal of non-HDL lipoproteins from a sample and assay of HDL cholesterol in the sample occur without interruption of the assay. The device also prevents interference by reagents used for the HDL assay with other assays carried out on the same sample.
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:
a. a sample distribution matrix for distributing the blood fluid sample in said assay device;
b. a reagent pad containing a reagent effective to selectively remove non-HDL lipoproteins from the fluid sample; and
c. an HDL assay element in which HDL concentration can be assayed, in direct contact with said reagent pad;
wherein said reagent pad may be brought into fluid communication with said sample distribution matrix.
2. The device of claim 1 , further comprising
a reaction bar to which said HDL assay element is attached, and mounting means attaching said reaction bar to said main body, effective to establish a displacement of said reaction bar between a sample distribution position, in which said HDL assay element and said reagent pad are spaced apart from said sample distribution matrix, and a test position, in which said HDL assay element is in fluid communication with said sample distribution matrix.
3. The device of claim 1 , wherein a lower surface of the MDL assay element is attached to an upper surface of the reagent pad.
4. The device of claim 1 , wherein said reagent is immobilized to said reagent pad.
5. The device of claim 1 , wherein said reagent includes a sulfonated polysaccharide.
6. The device of claim 1 , wherein said reagent pad is an asymmetric polymeric membrane, having a smaller pored surface and an opposite, larger pored surface, and is oriented such that its smaller pored surface faces the HDL assay element.
7. The device of claim 6 , wherein each of said HDL assay element and said reagent pad is an asymmetric polymeric membrane, and said membranes are attached such that the smaller pored surface of the reagent pad contacts a larger pored surface of the HDL assay element.
8. 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), the method comprising:
a. applying said blood fluid sample to a sample distribution matrix;
b. transferring said blood fluid sample from said matrix to a reagent pad containing a reagent effective to selectively remove non-HDL lipoproteins from the sample;
c. transferring said sample to an HDL assay element, which is in direct contact with said reagent pad, and in which HDL concentration can be assayed; and
d. determining the content of HDL lipoproteins in said sample;
wherein fluid communication is selectively establishable between said sample distribution matrix and said reagent pad.
9. The method of claim 8 , wherein step (b) comprises bringing said sample distribution matrix into fluid communication with a first surface of said reagent pad, and wherein an opposite surface of said reagent pad is in simultaneous contact with said HDL assay element, such that successive sample volumes proceed from said reagent pad to said HDL assay element.
10. The method of claim 8 , further comprising the step of breaking said fluid communication between the sample distribution matrix and said reagent pad, when a desired amount of sample has been transferred.
11. The method of claim 8 , wherein said reagent pad comprises an asymmetric polymeric membrane, having a smaller pored surface and an opposite, larger pored surface, and is oriented such that its smaller pored surface faces said HDL assay element.
12. The method of claim 11 , wherein each of said HDL assay element and said reagent pad is an asymmetric polymeric membrane, and said membranes are attached such that the smaller pored surface of the reagent pad contacts a larger pored surface of the HDL assay element.
13. The method of claim 8 , wherein said reagent effective to selectively remove non-HDL lipoproteins is immobilized to said reagent pad.
14. The method of claim 8 , wherein said HDL assay element comprises a biosensor.