• Korean Journal of Clinical Laboratory Science
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• v.44 no.3
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• pp.103-111
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• 2012

Low-Density Lipoprotein cholesterol (LDLC) is the most important marker for the treatment of hyperlipidemia in NCEP-ATP III(National Cholesterol Education Program-Adult Treatment Panel III) guideline. Therefore, LDL cholesterol is pathologically meaningful, accurate measurement should be a top priority. Currently, LDLC is directly measured in most cases, but, the estimate is still used in mass health examination or screening test. This study is about the comparison of LDL-Cholesterol direct measurement with the estimate using various formula (Friedewald: [LDL-F=TC-HDL-TG/5], Nakajima: [LDL-N=TC-HDL-TG/4], Hattori: [LDL-H =0.94TC-0.94HDL-0.19TG], Puavilai: [LDL-P=TC-HDL-TG/6], Carvalho: [LDL-C=3(TC-HDL)/4]) for calculating more accurate value. We analyzed total cholesterol (TC), try-glyceride (TG), high-density lipoprotein cholesterol (HDLC), and LDLC levels of 210 subjects between June and November in 2011. Until now, the Friedewald formula is the most commonly used estimate for the LDLC. When Friedewald formula was applied, the correlation coefficient (r) was 0.940, showing high correlation. But, the result of the direct method was significantly different, compared with those of the Friedewald formula in triglyceride levels ${\geq}400mg/dL$(p<0.05). There was the highest correlation when we used LDL-P formula(r=0.947) in triglyceride levels <400 mg/dl. Also there was the lowest mean difference regardless of triglyceride level. Therefore, the study showed that TG/6 is more precise means of calculation than TG/5. On the other hand, the calculation of LDL-Cholesterol was underestimated, compared with direct measurement. It is necessary to have more data and modified Friedewald formula should be used for the accurate calculation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5492-5500
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• 2015

Low-density lipoprotein cholesterol (LDL-C) is a major modifiable risk factor for cardio- cerebrovascular disease. In clinical practice, however, it is primarily calculated using the Friedewald formula as a cost-effective method. The aim of this study was to compare Friedewald-estimated and directly measured LDL-C values and assess the concordance in guideline LDL-C risk classification between the two methods. The data were derived from the 2009 and 2010 Korea National Health and Nutrition Survey (KNHANES). Analysis was done for 4,319 subjects with lipid panels-total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), directly measured LDL-C using an enzymatic homogeneous assay, and triglycerides (TG). For subjects with TG lower than 400 mg/dL, Friedewald-estimated and directly measured LDL-C were highly correlated (r = 0.958, p < 0.001) and overall concordance was 82.7%. As TG increased, overall concordance decreased. Overall concordance was 85.4% at TG lower than 150 mg/dL; 78.2% at TG of 150-199 mg/dL; and 71.4% at TG of 200-399 mg/dL. The Friedewld equation tended to overestimate LDL-C when TG are of < 150 mg/dL; however, underestimate LDL-C when TG are of ${\geq}150mg/dL$. As a result, Friedewald estimation misclassified 382 subjects (9.1%) in a higher category versus 348 subjects (8.3%) in a lower category. Our findings suggest that overestimation of LDL-C by the Friedewald formula can be a great problem as well as underestimation.

• Korean Journal of Clinical Laboratory Science
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• v.45 no.2
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• pp.54-59
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• 2013

NonHDL cholesterol values have been suggested as a risk marker for cardiovascular disease. NonHDL cholesterol values were calculated, using a very simple measurement [nonHDL cholesterol=serum total cholesterol-HDL cholesterol]. This formula is very useful as a screening tool for identifying dyslipoproteinemias, risk assessment, and assessing the results of hypolipidemic therapy. The data from the 2009 Korean National Health and Nutrition Examination Survey were used. Analysis was done for 1,992 subjects with lipid panels (Cholesterol, HDL, LDLdirect and Triglycerides) results. We studied the relationship between nonHDL cholesterol and LDL cholesterol. As a result, nonHDL cholesterol values were plotted against the LDL direct and calculated values. The linear regression equation for nonHDL cholesterol and direct LDL cholesterol was $nonHDLchol=23.60+1.03{\times}LDLdirect$ (p<0.0001, $r^2=0.80$) in all subjects. The subjects were classified into triglyceride values. When triglycerides are below 400 mg/dL, the linear fit to LDL direct is found to be $[nonHDLchol=17.34+1.07{\times}LDLdirect]$ (p<0.0001, $r^2=0.88$) and to the Friedewald LDL calculation is $[nonHDLchol=23.10+1.02{\times}LDLcalc]$ (p<0.0001, $r^2=0.82$). For triglycerides above 400 mg/dL, the linear fit equation is $[nonHDLchol=87.57+0.92{\times}LDLdirect]$ (p<0.0001, $r^2=0.50$) and to the LDL calculated, it is $[nonHDLchol=142.70+0.50{\times}LDLcalc]$ (p<0.0001, $r^2=0.32$). This study provides examples of the utility of nonHDL cholesterol concentrations in clinical medicine.