[Adaptation of the enzyme method to determine the cholesterol content of high density serum lipoproteins isolated using the precipitation method].

Negative interference was established of the precipitating reagent (heparin/MnCl2) for the isolation of HDL in the determination of serum concentration of high density lipoproteins--cholesterol by the enzyme CHOD-PAP method. The combining of enzyme-substrate reagent with 8,0 mmol/l EDTA eliminated the negative interference, but induced a lightly manifested increase of the optical density regardless of cholesterol concentration. That is the reason, the calibration of the enzimatic method is recommended to be performen with cholesterol standards, pretreated with precipitating reagent, analogically to serum. The analytical significance of the modified method was studied as regards reproducibility (VK = 0,88% with investigation in series and VK = 4,57% with investigation in time) and of accurary (test of Lord, L = 0,073 less than Lp less than 0,05).