Dual HDL/total Cholesterol Test: A Single-Tube, Homogeneous Assay for Sequential Measurement of HDL Cholesterol and Total Cholesterol

Abstract

The quantitation of cholesterol in lipoprotein subfractions is valuable in estimating the risk for coronary artery disease, but requires multiple tests. We describe a relatively simple procedure, referred to as the dual HDL/total cholesterol (DHT) assay, which allows the sequential measurement of HDL 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-apolipoprotein B [apo(B)] antibody, which sterically blocks the enzymatic measurement of cholesterol on the non-HDL subfractions. Next, deoxycholate is added, which disrupts the antibody-apo(B) complex and allows the subsequent enzymatic measurement of the remaining cholesterol in the non-HDL subfractions. The DHT assay has an acceptable analytical performance and yields results similar to standard methods: for HDL-C, γ(DHT) = 0·98 x+0·19, r = 0·90; for total-C, γ(DHT) = 1·11 x–0·09, r = 0·99. In summary, the DHT assay is a homogeneous assay for both HDL-C and total-C, and provides a simple and cost-effective method for screening for hyperlipidaemia.