How should low-density lipoprotein cholesterol concentration be determined?

The National Cholesterol Education Program Adult Treatment Panel III Report (NCEP-ATP III) has identified low-density lipoprotein cholesterol (LDLC) as the primary target of therapy and has recommended using the Friedewald calculated LDL-C (CLDL- C). The present study compared a direct LDLC (D-LDL-C) method with the C-LDL-C and determined the possible impact on treatment decisions. C-LDL-C and D-LDL-C were compared in 464 consecutive patients. The D-LDL-C was 18% higher than the C-LDL-C at 100 mg/dL, an important level for medical decision making. This can result in inappropriate drug therapy (usually overtreatment) if the NCEP-ATP III treatment guidelines are followed with the D-LDL-C rather than the C-LDL-C. The C-LDL-C is preferred because this assay has been used in clinical trials documenting the benefits of cholesterol-lowering therapy.