Dual HDL/total cholesterol test: a single-tube, homogeneous assay for sequential measurement of HDL cholesterol and total cholesterol

The quantitation of cholesterol in lipoprotein subfractions is valuable in estimating the risk for coronary artery disease, but requires multiple test s. We describe a relatively simple procedure, referred to as the dual HDL/t otal cholesterol (DHT) assay, which allows the sequential measurement of HD L cholesterol (HDL-C) and total cholesterol (total-C) in a single tube. HDL -C is first measured using a homogeneous assay that utilizes an anti-apolip oprotein B [apo(B)] antibody, which sterically blocks the enzymatic measure ment of cholesterol on the non-HDL subfractions. Next, deoxycholate is adde d, which disrupts the antibody-apo(B) complex and allows the subsequent enz ymatic measurement of the remaining cholesterol in the non-I-IDL subfractio ns. The DHT assay has an acceptable analytical performance and yields resul ts similar to standard methods: for HDL-C, y(DHT)=0.98x+ 0.19, r=0.90; for total-C, y(DHT)= 1.11x-0.09, r=0.99. In summary, the DI-IT assay is a homog eneous assay for both HDL-C and total-C, and provides a simple and cost-eff ective method for screening for hyperlipidaemia.