COMPARISON AND CORRELATION BETWEEN LOW DENSITY LIPOPROTEIN LEVELS ESTIMATED BY DIRECT METHOD VERSUS INDIRECT METHOD USING FRIEDWALD FORMULA IN PATIENTS PRESENTED TO OUR TERTIARY CARE HOSPITAL

Abstract

Introduction: One of the major risk factors for the development of coronary heart disease is high low-density lipoprotein (LDL) cholesterol. Reduction in LDL cholesterol levels decreases the risk of development of coronary heart disease. The optimum LDL levels in a normal healthy individual have to be maintained at a concentration of

<100 mg/dL.

Objectives: the present study aimed to estimate, compare and correlate LDL concentration measured at different levels of TG levels by direct and indirect method in patients attending our tertiary care hospital.

Methodology: We included a total of 200 patients who have been referred to clinical biochemistry laboratory for lipid profile, out of 200 subjects 124 were males 76 were females. We divided the total subjects into three groups depending on the levels of triglycerides. Lipid profile parameters [total cholesterol, Tag, LDL, HDL, VLDL] were estimated in a fully automated biochemistry analyser as per the manufactures instructions. LDL was also calculated by Friedwalds formula: LDL = Total cholesterol-HDL-TG/5 (VLDL cholesterol). Student t test was used for the comparison of LDL concentration by direct and indirect method and Pearson’s Correlation coefficient was used to check the correlation.

Results: In the present study, we found strong correlation between direct method and Friedewald formula calculated LDL levels in subjects having triglyceride concentration less than 400 mg/dL. We found no statistical significant differences in LDL levels in Group I, II and III respectively and also we found strong positive correlation existed between the two methods for the determination of LDL levels.

Conclusion: Friedewalds Formula can be used to estimate LDL cholesterol, and direct LDL should be employed only in those cases wherein Friedewalds formula cannot be used like non-fasting samples, patients with TGs more than 400 mg/dl, disorders related to lipoproteins (Type III hyperlipoproteinemia) and secondary hyperlipoproteinemias.