Analytical performance of direct LDL-cholesterol assay compared with friedewald LDL-cholesterol and apolipoprotein B assay.

ABSTRACT

Clinical laboratory currently estimate low-density lipoprotein cholesterol using the Friedewald formula, which requires fasting specimens and is subject to error with increasing triglyceride levels. The direct LDL Immunoseperation Reagent for LDL-cholesterol assay also have some disadvantages 1. pipetting sample, 2. mixing and 3. centrifugation before subsequent measurement of cholesterol by conventional assay. We describe a rapid non-percipitating LDL-cholester assay using tentaclepolynion (PAMPS) reagent which base on precision with within-run and run-to-run coefficients of variation less than 3%. Results are in good agreement with the apolipoprotein assay (direct LDL-C = 1.745 apolipoprotein B-49.764 mg/dL, r=0.805) and also show very good linear regression with Friedewald LDL-C which triglyceride level below 400 mg/dL (Friedewald LDL-C=0.978 direct LDL-C-1.616 mg/dL, r=0.968). This method overcomes drawbacks the Friedewald formula and appears to be useful tool in managing hyperlipidemic patients by using an accurate quantification of LDl-C in the routine laboratory.