HIGH-DENSITY-LIPOPROTEIN CHOLESTEROL IN HEPARIN MNCL2 SUPERNATES DETERMINED WITH THE DOW ENZYMIC METHOD AFTER PRECIPITATION OF MN-2+ WITH HCO3-

  • 1 January 1984
    • journal article
    • research article
    • Vol. 30  (6) , 839-842
Abstract
Manganese interferes with enzymic cholesterol methods. High density lipoprotein (HDL) cholesterol was enzymatically measured in heparin-Mn2+ supernates treated with NaHCO3 (91 mmol/l) to precipitate Mn2+, and the results were compared with those by an automated Liebermann-Burchard method. For untreated supernates of 96 fresh [human] plasma samples, the enzymic values were 10.4% higher than comparison-method values, a bias that declined to +2.3% for treated supernates. For 72 sera promptly frozen and stored after collection, the enzymic values for untreated and treated supernates were, respectively, 6.0 and 0.5% higher than comparison-method values. In all cases, the magnitude of the bias was independent of the concentrations of cholesterol, triglyceride and HDL-cholesterol. Enzymic HDL-cholesterol measurements in NaHCO3-treated heparin-Mn2+ supernates prepared from 4 pooled serum controls agreed within 21 mg/l with values established for these pools by the Centers for Disease Control. The accuracy of enzymic HDL cholesterol measurements in heparin-Mn2+ supernates apparently is considerably increased by treatment with NaHCO3. [The association between HDL and an increased risk for ischemic heart disease is discussed.].