Current Understanding in the Measurement of Low Density Lipoprotein Cholesterol: A Comparison of Direct Measurement by Homogenous Assays versus Calculations

To compare the results obtained by direct homogenous assay for LDL-C to those obtained by Friedwalds and Anandrajas formulas with the assumption that the results obtained by direct assay are most accurate. This was a comparative study for the estimation of LDL-C using two different types of calculation formulas and direct estimation of LDL-C by homogenous method.

Serum Lipids and lipoproteins were measured in 505 fasting samples. Serum Total cholesterol was measured using CHOD-PAP method first described by Stadman on Siemens Dimensions Clinical Chemistry RXL Analyzer. Triglycerides were measured by Glycerol Phosphate peroxidase-PAP method. Direct LDL-C was measured by a homogenous assay by siemens diagnostics. A-HDL was measured by a homogenous method which uses PEG-cholesterol esterase using kit from siemens diagnostics. This was a comparative study for the estimation of LDL-C using two different types of calculation formulas and direct estimation of LDL-C by homogenous method.

A good correlation was found between D-LDL as compared to both F-LDL and A-LDL. Pearsons coefficient of correlation between F-LDL & D-LDL was 0.891 (p<0.001) which was comparatively better than that between A-LDL & D-LDL which came out to be 0.850.

In conclusion, regarding patients convenience, financial reasons and accuracy we support the reliability of Anandrajas formula as indirect low density lipoprotein estimation-in Punjabi population.