Abstract
There is an upsurge of interest in the serem high-density lipoproteins (HDL), because of their suggested role in atherosclersis and coronary heart diseases.This results in an increased demand for HDL quantitation in the clinical laboratory.To adopt as a routine test, two main questions should have been solved;l) choice of a precipltation method, among others, and 2) methodology of cholestrol determination.
Concerning the first question, we studied several precipitation methods, using the ultracentrifugation method as the reference.Following results were obtained;DS-Mg++method, -2.0%, Pht-Mg++method, +1.7%, Heparin-Ca++method, +3.7%, and Heparin-Mn++ (46mM/l) method, +4.1%.Recovery rates for a-Lipoprotein were (a-lipoprotein content of the original serem was considered as 100%), 93%, 94%, 108%, and 94%, respectively, and HDL contents within the precipitates were 8%, 6%, 0%, and 6% in respective precipitation method.
When enzymatic methods are applied for cholesterol determination, POD-4AA-Phe system was thought to be unsuitable, in terms of sensitivity and interference by the presence of bilirubin and ascorbic acid.In POD-4AA-DMAsystem, however, if determinations were made with absorbance at 550nm, the interference by bilirubin was largely nullified in comparison with the Abell'smethod.Negative interference by ascorbic acid was eliminated by addition of ascorbate oxidase into the system.
