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Friedewald’s formula (FF) is the most widely used formula in clinical practice to calculate low-density lipoprotein cholesterol (LDLC) from total cholesterol (TC), triglyceride (TG) and high-density lipoprotein cholesterol (HDLC). But this formula frequently underestimates LDLC. The aim of this study was to derive a regression equation (RE) to abolish the underestimation and to compare the performance of RE and FF in Bangladeshi population. RE was derived from 531 lipid profiles (equation derivation group) for the calculation of LDLC by multiple linear regression analysis. The RE was then used to calculate LDLC in another 952 subjects (equation validation group). LDLC calculated by RE and FF were compared with measured LDLC by appropriate statistical analyses. In equation validation group, measured LDLC, LDLC calculated by RE and FF were 2.97±0.81, 2.91±0.80 and 2.72±0.93 mmol/L respectively. Precision (r) was 0.9525 for RE and 0.9193 for FF. Passing & Bablok linear regression equations against measured LDLC were y = 0.9792x + 0.007 for RE and y = 1.1412x – 0.6781 for FF. Accuracy within ±12% of measured LDLC was 79% and 57% for RE and FF, respectively. The derived RE is more accurate than FF for the calculation of LDLC in Bangladeshi population. Keywords: Lipoprotein cholesterol; Friedewald’s formula; Bangladeshi population. © 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v6i1.14864 J. Sci. Res. 6 (1), 143-152 (2014)

Objective: A modification of Friedewald’s formula was proposed to calculate LDL cholesterol in Bangladeshi population up to serum triglyceride concentration of 1000 mg/dL. The aim of this study was to validate the modification of Friedewald’s formula in Bangladeshi population.Methods: Serum total cholesterol, triglyceride, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol concentrations were measured in specimens obtained form 314 adult Bangladeshi subjects selected conveniently. LDL cholesterol concentrations were also calculated by modified Friedewald’s formula and original Friedewald’s formula. Results were expressed as mean ± SD and calculated LDL cholesterol was compared with measured LDL cholesterol by two-tailed paired t test and Pearson’s correlation coefficient (r).Results: The mean ± SD of measured LDL cholesterol was 138.3 ± 54.58 mg/dL. LDL cholesterol calculated by modified Friedewald’s formula and original Friedewald’s formula were 135.9 ± 59.26 mg/dL (P>0.05) and 123.5 ± 65.75 mg/dL (P

A modification of Friedewald’s formula to estimate serum low-density lipoprotein cholesterol (LDLC) up to serum triglyceride (TG) level of 11.3 mmol/L in Bangladeshi population has recently been published. The aim of this study was to compare the modified formula with direct measurement of LDLC in Bangladeshi population in a different setting. One thousand and fifty two specimens from adult subjects were analyzed. Serum total cholesterol (TC), high-density lipoprotein cholesterol (HDLC), LDLC and TG were measured by standard methods. The modified Friedewald’s formula was applied to estimate LDL cholesterol concentration. Results were expressed as mean ± SD and calculated LDLC was compared with measured LDLC by two-tailed paired t test, Bland-Altman plot for absolute bias, Pearson’s correlation coefficients of calculated LDLC with measured LDLC and Passing & Bablok regression equation of calculated LDLC against measured LDLC. The mean ± SD of measured LDLC was 2.98±0.82 mmol/L. LDLC calculated by modified Friedewald’s formula was 2.77±0.86 mmol/L. The mean absolute bias was –0.20±0.32 mmol/L, Pearson’s correlation coefficient (r) was 0.9293 (P

Keywords: Glycosylated hemoglobin; low-density lipoprotein cholesterol, type 2 diabetesDOI: 10.3329/bjpath.v25i1.4125Bangladesh J Pathol 25(1): 10-13

Friedewald’s formula is the most frequently used formula for the calculation of serum lowdensity lipoprotein cholesterol from serum total cholesterol, serum triacylglycerol and serum high-density lipoprotein cholesterol. Most laboratories use serum triacylglycerol concentration of 400 mg/dl as upper cut-off limit for the calculation of LDL cholesterol, but a combination of serum triacylglycerol to total cholesterol ratio and serum triacylglycerol may have more advantages than serum triacylglycerol concentration alone to use Friedewald’s formula effectively. The aim of this study was to determine the upper cut-off limit of serum triacylglycerol concentration and serum triacylglycerol to total cholesterol ratio to calculate LDL cholesterol using Friedewald’s formula in Bangladeshi population. Serum total cholesterol, serum triacylglycerol, serum high-density lipoprotein cholesterol and serum lowdensity lipoprotein cholesterol were measured by direct method on 644 sera obtained from adult Bangladeshi study subjects after 12 hours of fasting. Serum low-density lipoprotein cholesterol was also calculated by using Friedewald formula. Low-density lipoprotein cholesterol obtained by Friedewald’s formula in this study was compared with that obtained by direct method in different level of triacylglycerol and also in different triacylglycerol to total cholesterol ratio. Friedewald’s formula underestimates low-density lipoprotein cholesterol when serum triacylglycerol concentration >300 mg/dL. But when direct serum low-density lipoprotein cholesterol was compared with low-density lipoprotein cholesterol calculated using Friedewald’s formula up to serum triacylglycerol to total cholesterol ratio of 2, underestimation subsides, and the serum triacylglycerol level up to 700 mg/dl could be confidently included for the calculation of low-density lipoprotein cholesterol by Friedewald’s formula. Friedewald’s calculation formula can be confidently used up to serum triacylglycerol concentration of 700 mg/dl in Bangladeshi population, provided the serum triacylglycerol to total cholesterol ratio is two or less. Key Words: Friedewald Formula; Low-Density Lipoprotein Cholesterol