A comparative analysis of direct LDL-C assay and Friedewald’s formula in subjects of ischemic heart disease & stroke in a tertiary care centre

Introduction: Among the various risk factors for the development of Ischemic heart diseases (IHD) as well as stroke is elevated low density lipoprotein cholesterol (LDL-C) levels. This makes accurate reporting of LDL-C crucial in the management of IHD. On one hand estimation of LDL-C by direct method is available, but it is expensive and on the other hand the Friedewald's formula is most commonly employed but a method with limitations. Aim: Therefore the aim of this study is to evaluate the correlation between calculated LDL-C with direct LDL-C method and analyse their appropriateness. Materials and Methods: This study was a hospital based cross-sectional study. LDL-C was measured by both Friedewald's formula (FF) and direct LDL method in 501 participants between the age group of 30–70 years. Paired t-test was used to test the difference in LDL concentration obtained by a direct method and Friedewald's formula. The level of significance was taken as P < 0> Results: The mean and standard deviation (SD) of LDL-C estimated by both direct assay and FF showed a significant difference (p<0>0.05) at TG range >400 mg/dL. There was a discrepancy of 37 out of 501participants (7.38%) classified as cardiac risk groups by the two methods used. A significant correlation between LDL-C levels obtained by FF and direct methods, (p value <0 xss=removed xss=removed> Conclusion: The study concludes that both methods can be employed depending on TG levels. Direct LDL estimation appears to be unreliable at TG concentrations >400 mg/dL but useful when sample is collected from a non-fasting participants.