Homogeneous assay for direct determination of high-density lipoprotein cholesterol evaluated
Nauck, M.; März, W.; Haas, B.; Wieland, H.
Clinical Chemistry 42(3): 424-429
1996
ISSN/ISBN: 0009-9147 PMID: 8598107 Document Number: 464539
We evaluated a new homogeneous assay for quantifying high-density Lipoprotein cholesterol (HDL-C). The assay included four reagents: polyethylene glycol for "wrapping" chylomicrons, very-low-density lipoproteins (VLDL), and low-density lipoproteins (LDL); antibodies specific for apolipoprotein (apo) B and apo C-III to produce aggregates of chylomicrons, VLDL, and LDL; enzymes for the enzymatic cholesterol determination of the noncomplexed fipoproteins with 4-aminoantipyrine as the color reagent; and guanidine salt to stop the enzymatic reaction and to solubilize the complexes of apo B-containing lipoproteins, which would otherwise interfere with the reading of absorbance. The total CVs of the new method ranged between 2.4% and 8.4%. The HDL-C values (y) were in good agreement with those by a comparison phosphotungstic acid/MgCl-2 method (x): y = 0.987x + 17.2 mg/L (68th percentile of the residuals on the regression line = 21.49, r = 0.970). At triglyceride concentrations of 20 g/L (Intralipid) the homogeneous HDL-C concentrations increased by 2%. Hemoglobin markedly increased the results, whereas bilirubin reduced them. The homogeneous HDL-C assay was easy to handle and allows full automation. This test should considerably facilitate the screening of individuals at an increased risk of cardiovascular disease.