Effect of low serum triglyceride on LDL-cholestrol estimation by friedewald formula

Resumen

The aim of the current study was to investigatethe impact of low serum triglyceride (TG) onLDL-cholestrol estimation by Friedewald formula.Methods: Serum samples were taken from 540patients and divided into 4 groups based on the levelof the TG 100>, 100-150, 150-250 and 250-400 mg/dl.The total cholestrol (TC), TG, high density lipoprotein(HDL) and low density lipoprotein (LDL) were measured.Then, the LDL of patients whose serum levels ofTG>400 was measured with the direct method and calculatedas follows: Friedewald method= LDL – C (mg/dl) = TC–TG/5 – HDL. The results of Friedewald formulacompared with the direct measurement results. Findings:According to the results, a significant differenceobserved between Cholesterol (LDL-C) measured bythe direct method than Friedewald equation in patientswith TG>400 levels (P<0.001). No significant differenceswere observed in patients with TG 250-400 levels(P>0.05). A correlation reported between LDL-C measuredby the direct and Friedewald Equation methods(P<0.001). Conclusion: These results suggested therewas higher difference of LDL-C in low TG levels (100>and 100-150 mg/dl) measured by direct method andFriedewald Equation formula. Negligible differences observedin high TG levels (150-250 and 250-400 mg/dl)using direct method and Friedewald Equation formula.With increased TG levels (up to 400mg/dl), the overestimationof the LDL-C level is decreased by Friedewaldformula. So, in high TG levels, Friedewald Equation formulais reliable.