To compare the total cholesterol and HDL-cholesterol before and after ultra-centrifugation in lipemic samples

It is an everyday routine in laboratories to encounter interference in the analysis of lipids. These likely interferences (hemolysis, icterus and lipemia) are countered by asking physicians and patients to send fresh and properly collected samples. At the Aga Khan University (AKU) Laboratory, we receive 2-3 lipemic/turbid samples per day. Previously it was our departmental policy to advise these patients to go for lipoprotein electrophoresis, which though accurate was time consuming and not cost effective. We therefore studied ultra centrifugation/airfuge as an alternate method to clear lipid interference and provide accurate, reliable and cost effective results.

Daily 2-3 grossly turbid samples are identified on the lipid bench, 48 samples were received in 4 months (February to May 2004). These samples were analyzed for total cholesterol (TC) and High Density Lipoprotein-Cholesterol (HDL-C) before and after ultra centrifugation/airfuge.

There was a positive correlation between the lipemia and the false high TC and HDL-C. The mean TC and HDL-C before ultra centrifugation were 263.06 mg/dl and 39.42 mg/dl respectively and after centrifugation these became 191.77 mg/dl and 33.06 mg/dl. P value showed a significant difference in both results.

This study suggests that the removal of turbidity by ultra centrifugation/airfuge is cost effective, less time consuming and provides accurate reliable results of TC and HDL-C in patients with lipemia interference.