Low density lipoprotein cholesterol (LDL-c) is associated with the risk of atherosclerosis and coronary heart disease. Currently the clinical chemistry laboratory estimates of LDL-c using the Friedewald calculation requires a fasting sample and triglyceride to be lower than 400 mg/dl. With the kit reagent from Roche Diagnostic, Thailand, we evaluated the determination of direct LDL-c by homogeneous enzymatic assay performed by using the Hitachi 917 automatic analyzer.

The results from this study showed the direct result of the LDL-c method had a good accuracy and precision with “with in run” percentage CV were 0.50 and 0.69 for the low and high values and between run percentage CV of 1.19 and 0.84 in low and high values, respectively. The comparison of LDL-c by Friedewald calculation and homogeneous enzymatic assay, showed a good correlation (r=0.993, y=1.033x+12.715)

The direct LDL-c is a reasonably specific, accurate, precise method which is recommended to replace the Friedewald calculation. However, the method only approximates LDL-c and is subject to well estabished limitations, but request only LDL-c is cheaper than the Friedewald calculation.