Background: 2 homogeneous assay kits, Determiner L HDL-C from Kyowa Medex, Co., Ltd. (Tokyo, Japan) (KWM) and Cholestest NHDL from Daiichi Pure Chemical, Co., Ltd. (Tokyo, Japan) (DIC), for HDL-C are widely used in laboratory tests worldwide. Meanwhile, it was reported that free cholesterol (FC) in HDL is not measured with one of these kits. We devised a novel evaluation method and analyzed the 2 kits in detail. Methods: Using HPLC, the residual amounts of cholesterol in reaction mixtures were compared before and after reaction with homogeneous reagents. Healthy sera were reacted with homogeneous reagents or with heated, non-enzyme reagents from each kit. The FC and total cholesterol in each lipoprotein were continuously measured with HPLC. Results: With KWM, the HDL-C was measured >95%. With DIC, all FC in sera was eliminated in the first reaction, and FC in HDL was not measured. Moreover, the peak X that was assumed to be a part of HDL was separated with DIC, and the cholesterol in the peak X was not measured. Conclusions: 2 HDL-C assay kits were compared using a novel evaluation method. KWM was good overall. DIC was found to have 2 problems: 1) FC in HDL was not measured, and 2) the cholesterol in peak X that was assumed to be a part of HDL was not measured. (C) 2008 Elsevier B.V. All rights reserved.
