Evaluation of quality-control materials for high-density-lipoprotein cholesterol quantitation

Area of Science:

• Clinical Chemistry
• Lipid Metabolism
• Biochemical Assays

Background:

• Accurate quantitation of high-density lipoprotein (HDL) cholesterol is crucial for cardiovascular disease risk assessment.
• Standardized and reliable quality-control materials are essential for validating HDL cholesterol measurement methods.

Purpose of the Study:

• To evaluate the suitability of various commercial and in-house prepared serum and plasma pools as control materials for HDL cholesterol quantitation.
• To compare the performance of precipitation-based methods with ultracentrifugal and electrophoretic methods for HDL cholesterol measurement.

Main Methods:

• Evaluation of commercial quality-control materials and frozen plasma/serum pools.
• Comparison of heparin-Mn2+ and phosphotungstate-Mg2+ precipitation methods against ultracentrifugal and electrophoretic techniques.
• Assessment of among-day precision, inter-method differences, lipid composition, and electrophoretic mobility.

Main Results:

• Frozen plasma and serum pools, along with a modified commercial lyophilized serum (Analytical Control), were found to be suitable HDL control materials.
• Conventional lyophilized pools exhibited poor between-day precision and significant inter-method differences, deeming them less suitable.
• A serum pool stabilized with ethylene glycol was found to be the least appropriate control material.

Conclusions:

• In-house frozen pools and specific commercial preparations are recommended as reliable HDL cholesterol control materials.
• Careful selection of quality-control materials is critical to ensure accurate and reproducible HDL cholesterol measurements.
• Further investigation into novel lyophilized pools (Lipid Fraction Control, Lipidophor) is warranted due to promising initial results.