Comparison of direct and precipitation methods for the estimation of major serum lipoproteins

Abstract

Background: There is increase in use of direct assays for analysis of high and low density lipoprotein cholesterol by clinical laboratories despite differences in performance characteristics with conventional precipitation methods. Calculation of low density lipoprotein cholesterol in precipitation methods is based on total cholesterol, triglycerides and high density lipoproteins, thus may cumulatively carry errors of individual methods. Adoption of direct assays is expected to decrease turnaround time and save on cost.

Objectives: To compare direct and precipitation methods for estimation of major serum lipoproteins.

Design: Cross sectional study.

Setting: Clinical Chemistry Laboratory, Kenyatta National Hospital, Nairobi, Kenya.

Subjects: Three hundred and eighty four (384) participants were recruited for the study.

Results: There was no significant difference in high density lipoprotein cholesterol estimated by direct and precipitation methods p=0.091 as well as low density lipoprotein cholesterol estimated by direct method and Friedwald’s formulae p=0.093.

Conclusion: Both direct and precipitation methods give similar results. Selection should be based solely on workload, availability and technical expertise.