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.