Abstract

In 2005 Abbott removed its hCG-kit (in vitro test 3A63-20) from the German market without any further notice. Later on the worldwide distribution was stopped. Up to this time this microparticle enzyme immunoassay (MEIA) was used by our laboratory for the screening of human Chorionic Gonadotropin [hCG] misuse. For any necessary confirmation of suspicious samples after screening the total β-hCG-kit (in vitro test 1A06-22) from Abbott was applied. Both kits were easy to handle and fulfilled the criteria of sensitivity, minimum required performance limit of 5 mIU/ml urine, according to the anti-doping regulation of the World Anti-doping Agency [WADA]. The two Abbott MEIA kits were performed with the same IMx® benchtop machine, whereas the antibody binding site (epitope) of both kits were different. The epitope of the IMx® hCG-kit was an anti-common a: anti-ß C-terminal epitope showing specifity for nicked and non-nicked hCG. The IMx® total ß-hCG kit is an anti-ß C-terminal: anti-common b1 epitope, specific for nicked and nonnicked hCG as well as for the free ß subunit. The Abbott IMx® machine is followed by the AxSYM® system Plus, but only offering a total ß-hCG kit. The AxSYM® system offers a wide range of different analytical parameters for clinical diagnostics. This system is very space consuming in comparison to the well established IMx® machine. Due to these disadvantages we looked for a cost-effective alternative method. The screening procedure for about 7000 samples per year was changed. We decided to use the Abbott IMx® total ß-hCG kit for routine analysis and chose the Elecsys® hCG STAT kit (Roche Diagnostics) for confirmation, due to the availability of this system at our university. The applied electro chemiluminescence immuno assay [ELICA] is able to detect the intact holo-hormone (with epitope anti-hCG dimer: anti-common ß2). The free ß-subunit as well as nicked hCG forms will not be recognized. According to the manufacturer the test was only validated for plasma. It shows low cross reactivity with LH and FSH and no cross reactivity with TSH according to the manufacturer's description. A manufacturers comparison with the Abbott IMx® hCG kit showed a good correlation (r = 0,96). For application in doping analysis a validation of the Elecsys® System 2010, hCG STAT kit was performed for hCG in urinary matrix and is described in detail. The results of both systems have been compared. Einleitung (geändert)