title: Measurement of inhibin A: a modification to an enzyme-linked immunosorbent assay.
abstract: Inhibin A is a useful prenatal marker of Down syndrome. Currently, the available enzyme-linked immunosorbent assays (ELISAs) for inhibin A are based upon the same paired monoclonal antibodies. In the present study we have confirmed for one of those ELISAs that short-term sample storage as whole blood leads to a significant decline in detectable inhibin A and that this is most likely due to erythrocyte catalase interference with a critical oxidation step in the assay. While this interference can be eliminated by heating the samples pre-assay, this process is labour intensive. In the present study we have demonstrated that the addition of 3-amino-1,2,4-triazole (AT), a catalase 'suicide' inhibitor, also prevents the decline of inhibin A levels in samples stored as whole blood. We suggest that the addition of AT to samples prior to assay is a simple modification to the inhibin A ELISA that affords optimum performance.
authors.affiliation: Centre for Women's Health Research, Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia.
authors.forename: P P
authors.initials: PP
authors.lastname: Thirunavukarasu
authors.forename: E M
authors.initials: EM
authors.lastname: Wallace
mesh_terms: D000640:Amitrole / Q000494:pharmacology; D004314:Down Syndrome / Q000175:diagnosis*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D007265:Inhibins / Q000097:blood* / Q000187:drug effects; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis; D013048:Specimen Handling
chemical_list: D004791:Enzyme Inhibitors; D007265:Inhibins; D000640:Amitrole