||The cholesterol reagent kit is composed of cholesterol esterase, cholesterol oxidase and the reagents for Trinder reaction. Cholesterol ester is catalyzed by cholesterol esterase and cholesterol oxidase to produce hydrogen peroxide (H2O2). H2O2 is then catalyzed by the peroxidase in the presence of phenol and 4-amino-antipyrine. The product, quinine, can be quantified with measuring optical density at 500 nm. In this work, blood serum was quantified using three different cholesterol reagent kits. In the accuracy test, standard cholesterol was used to survey the accuracy of instruments. In the specificity experiment, the cholesterol reagent kit can be used precisely when cholesterol concentration less than 200 mg/dL, suggesting the negative rate for this kind of measurement is very high. In the sensitivity test, the cholesterol reagent kit is very precise when cholesterol concentration greater than 300 mg/dL, suggesting the positive rate for this kind of measurement is very high. In the error experiments, the differences between the results were significantly. According to previous reports, there is no interference to reagent kit when the concentration of specific contents of serum sample falls in the following range: ascorbic acid density £ 2840 mmol/L, bilirubin density £ 342 mmol/L, hemoglobin density £ 2.00 g/L, and triglyceride density £ 22.6 mmol/L. We can conclude from these experiments that cholesterol reagent kit show high positive and negative rate in the clinical test. The error experiments show small variation, but the results are within the range of tolerance. Two importance indicators for clinical diagnosis are sensitivity and specificity. The cholesterol reagent kit passes both screening standards and is a very stable reagent for clinical diagnosis.