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Introduction: Spherical particles with nonpolar neutral lipids at the center and more polar amphipathic lipids at their surface are called Lipoproteins. High Density Lipoprotein (HDL) aids in cholesterol homeostasis by removing it from cells by several different mechanisms. The results of HDL Cholesterol (HDL-C) should be accurate and reliable, especially for the patients with borderline values, where the variation resulting from the methodology used may interfere with the interpretation of clinical scenario by the doctors. Aim: To compare the results of HDL values obtained by using three different technical methods. Materials and Methods: The present study was conducted using 30 serum samples from the Biochemistry laboratory of KLE Society's Dr. Prabhakar Kore Charitable Hospital and Medical Research Centre, Belagavi, Karnataka, India for HDL values, each for the three different technical methods (fully-automated, semi-automated and manual method). The data obtained was analysed statistically by computing descriptive statistics the mean, standard deviation and correlation coefficient. Results: Results of serum samples analysed for HDL-C values ranged from 31-79 mg/dL (mean 43.1) in fully-automated analyser, 28.06-75.18 (mean 39.6) in semi-automated and 27.06-62.7 mg/dL (mean 39.7) using manual method. There was significant difference in the mean values of HDL-C values obtained using the three different methods and positive correlation was established on comparing semi-automated and manual method (Semi-automated v/s manual method, r=0.827) and found to be statistically significant. Conclusion: As HDL estimation is routinely done in many of the clinical laboratories, a sound knowledge of the HDL values obtained using different techniques can help the clinicians while ordering for the test and also for diagnosing and monitoring of the cases with various lipid abnormalities. [ABSTRACT FROM AUTHOR]

Background: Estimation of low-density lipoprotein cholesterol is crucial in the management of ischemic heart disease patients. Low-density lipoprotein cholesterol is routinely calculated in laboratories world over by applying Friedewald formula for logistic reasons. We derived a new formula based on multiple regression approach., Methods: Lipid profiles were done on blood samples of 2008 patients. In initial 1000 patients, low-density lipoprotein cholesterol was estimated by a direct method and also by Friedewald formula. By applying linear regression methods on the data of direct estimation method, a new formula was obtained and the accuracy of this new formula was validated in the next 1008 patients., Results: The mean low-density lipoprotein cholesterol was 116+/-41.5 mg/dl (3.02+/-1.08 mmol/l) measured by direct low-density lipoprotein cholesterol assay and that calculated by Friedewald formula was 119+/-46 mg/dl (3.09+/-1.2 mmol/l) for the initial 1000 patients. Low-density lipoprotein cholesterol measured by direct low-density lipoprotein cholesterol assay and calculated from Friedewald formula showed good correlation (r = 0.88), however, there was minimal overestimation by the Friedewald formula. The correlation improved between direct low-density lipoprotein cholesterol and calculated low-density lipoprotein cholesterol after excluding the patients with triglycerides more than 350 mg/dl (r = 0.92). The mean low-density lipoprotein cholesterol measured by the direct assay and by new formula in the next 1008 patients was 117+/-40 mg/dl (3.04+/-1.04 mmol/l) and 113.7+/-37 mg/dl (2.96+/-0.96 mmol/l), respectively with very good correlation (r = 0.97) between them., Conclusions: The new formula derived from multiple linear regression analysis appears to be more accurate than Friedewald formula in Indian population.