[Determination of HDL-cholesterol].

Area of Science:

• Clinical Chemistry
• Biochemistry

Background:

• Clinical methods for HDL-cholesterol determination often involve precipitating apolipoprotein-B-containing lipoproteins.
• Ultracentrifugation methods serve as the gold standard but are expensive and impractical for routine use.

Purpose of the Study:

• To compare the effectiveness, practicality, and technical conditions of common precipitation techniques for HDL-cholesterol determination.
• To provide recommendations for harmonizing cholesterol determination methods in clinical practice.

Main Methods:

• Comparative analysis of precipitation techniques including heparin/MCl2, dextran sulphate/CaCl2, and phosphotungstic acid/MgCl2.
• Evaluation of factors influencing precipitation: reagent concentration, pH, temperature, incubation, and centrifugation.
• Assessment of cholesterol determination using enzymatic (CHOD-PAP) and chemical (Liebermann-Burchard) methods.

Main Results:

• Phosphotungstic acid precipitation is well-suited for enzymatic cholesterol determination (CHOD-PAP method).
• Dextran sulphate/CaCl2 (40 g/l, 2.0 mol/l) is recommended for chemical cholesterol determination (Liebermann-Burchard).
• Excessive precipitation with phosphotungstic acid and dextran sulphate/MgCl2 may lead to interferences and higher results in Liebermann-Burchard reactions.

Conclusions:

• The choice of precipitation method should be tailored to the specific cholesterol determination assay (enzymatic vs. chemical).
• Dextran sulphate/CaCl2 offers a practical and effective method for chemical cholesterol analysis.
• Harmonization of HDL-cholesterol determination requires careful consideration of precipitation reagent choice and assay conditions.