Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2010 May 21:9:52.
doi: 10.1186/1476-511X-9-52.

A modified formula for calculating low-density lipoprotein cholesterol values

Yunqin Chen  1 , Xiaojin Zhang, Baishen Pan, Xuejuan Jin, Haili Yao, Bin Chen, Yunzeng Zou, Junbo Ge, Haozhu Chen
Affiliations

A modified formula for calculating low-density lipoprotein cholesterol values

Yunqin Chen et al. Lipids Health Dis. .

Abstract

Background: The Friedewald formula (FF) is useful for calculating serum low-density lipoprotein cholesterol (LDL-C) values, but has a remarkable deviation and limitation especially in hypertriglyceridemia. We modify the formula which is now more suitable for LDL-C calculation.

Methods: 2180 cases were classified into three groups according to their TG concentrations (A: < 200 mg/dl, n = 1220; B: 200-400 mg/dl, n = 480; C: 400-1000 mg/dl, n = 480). The concentrations of LDL-C were measured or estimated by 1) a direct measurement (DM); 2) the FF; and 3) our modified Friedewald formula (MFF): LDL-C (mg/dl) = Non-HDL-C x 90% - TG x 10%.

Results: Linear regression showed a significant correlation (P < 0.001) between the measured and calculated LDL-C values. Bland-Altman plots indicated that the methods (DM/MFF) were in better agreement than those (DM/FF). The LDL-C/Non-HDL-C ratio in FF calculated values was significantly lower (P < 0.05) than that in MFF or DM values, while no significant difference between MFF and DM was found. In Group A and Group B, 4.26% and 14.79% of the MFF calculated values had more than 20% deviation from those measured by DM. These percentages were significantly lower than those calculated by FF, where 7.30% and 25.63% were observed, respectively (P < 0.01 and P < 0.001). The MFF calculated values were all positive even in Group C.

Conclusions: Compared with the FF calculation, serum LDL-C values estimated by our modified formula are closer to those measured by a direct assay. The modification significantly diminishes the interference caused by hypertriglyceridemia.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Correlations for LDL-C in subjects with different TG values. The LDL-C values were significantly correlated between the MFF and DM (P < 0.001)
Figure 2
Figure 2
Bland-Altman plots for LDL-C in subjects with different TG values. In the Bland-Altman plots the difference between the direct method (DM) and the formula method for LDL-C, depending on serum TG values, was plotted against the average of the methods
Figure 3
Figure 3
Ratios of LDL-C to Non-HDL-C values in subjects with different TG values. The LDL-C/Non-HDL-C ratio in FF calculated values was significantly lower in the groups with TG>200 mg/dl than that in MFF or DM values (P < 0.05), even in Group B (TG: 200-400 mg/dl), while no significant difference between the MFF and DM was found
See this image and copyright information in PMC

References

    1. Cheng AY, Leiter LA. Implications of recent clinical trials for the National Cholesterol Education Program Adult Treatment Panel III guidelines. Curr Opin Cardiol. 2006;21:400–4. - PubMed
    1. National Cholesterol Education Program (NCEP) Expert Panel. Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) final report. Circulation. 2002;106:3143–421. - PubMed
    1. Keevil JG, Cullen MW, Gangnon R, McBride PE, Stein JH. Implications of cardiac risk and low-density lipoprotein cholesterol distributions in the United States for the diagnosis and treatment of dyslipidemia: data from National Health and Nutrition Examination Survey 1999 to 2002. Circulation. 2007;115:1363–70. doi: 10.1161/CIRCULATIONAHA.106.645473. - DOI - PubMed
    1. Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem. 1972;18:499–502. - PubMed
    1. McNamara JR, Cohn JS, Wilson PW, Schaefer EJ. Calculated values for low-density lipoprotein cholesterol in the assessment of lipid abnormalities and coronary disease risk. Clin Chem. 1990;36:36–42. - PubMed

Publication types