LDL-cholesterol measurement in diabetic type 2 patients: a comparison between direct assay and popular equations

BACKGROUND: Low density lipoprotein –Cholesterol (LDL-C) is one of the main factors for assessment of cardiovascular disease risk and it is more important in diabetic patients. Various methods are currently used for LDL-C measurements which are compared in this study. METHODS: This study was conducted in Diabetes Research Center based on laboratory results of 1721 diabetic patients who referred to laboratory for regular follow-up of lipid profile. LDL-C was measured directly and also estimated according to Friedwald, Anandraja and Chen formulas. RESULTS: Results of direct LDL-C measurements were lower than all calculations at triglycerides (TG) levels less than 150 mg/dL while in higher TG levels direct measurement values were higher than Friedwald and Anandraja formula. Friedwald and Chen formula results had better correlation(r) with direct measurement than Anandraja in different levels of TG and also were able to define LDL-C > 100 mg/dL more accurately. CONCLUSIONS: Although we observed excellent correlation between the studied formulas with direct measurement, using the formula can misclassified diabetic patients with LDL-C values near threshold (100 mg/dL). However calculated LDL-C based on Chen and Friedwald formula can be a suitable alternative for direct measurement especially in regions with limited resources.