Turbiquant® Apolipoprotein A-I and Turbiquant® Apolipoprotein B

and Explanation Apolipoprotein A-I is the main protein component of the antiatherogenic HDL (high density lipoproteins). Apo A-I activates lecithin cholesterol acyltransferase which catalyzes the esterification of cholesterol. The resulting esterified cholesterol can then be transported to the liver, metabolized and excreted. Decreased concentrations of Apo A-I are a clear risk indicator for coronary disease1. Apolipoprotein B is the main protein component of LDL (low density lipoprotein) and accounts for approx. 95% of the total protein content of LDL and is also contained in the additional atherogenic lipoproteins VLDL, IDL and Lp(a). Apo B is necessary for the reaction with LDL receptors in the liver and on cell walls and is thus involved in transporting cholesterol from the liver to the vessel cell. Elevated levels of Apo B are frequently found in patients with atherosclerotic vascular changes and are a risk factor for atherosclerosis. Several studies have shown that the assay of apolipoproteins A-I and B is helpful in assessing the risk of atherosclerosis and has greater prognostic power than the sole determination of HDL and LDL cholesterol1,2. A particularly powerful parameter for estimating the risk of atherosclerosis is the quotient Apo B/Apo A-I. The higher the Apo B/Apo A-I quotient, the greater the risk of atherosclerosis. The determination of Apo B is also useful for monitoring the effectiveness of cholesterollowering therapy with statins2. Principle of the Method The proteins contained in human bodily fluids form immune complexes in an immunochemical reaction with specific antibodies. The increasing light absorption of the reaction mixture is then tracked photometrically. The maximum reaction velocity Vmax (peak-rate method) and the time (tVmax) required to reach Vmax is dependent on the concentration of the analyte in the sample3. The evaluation is performed by comparing the measured reaction parameters with the values obtained for a reference preparation. The reference curve is dependent on the lot, and is included with each pack of reagent in the form of a barcode. This also allows an automatic temperature compensation.