Evaluation of commercially available ELISA test kits for the detection of clenbuterol and other beta 2-agonists.

This article presents the results of a comparative study of nine commercially available ELISA test kits for clenbuterol and other beta 2-agonists currently being used in veterinary drug residue control of live and slaughtered animals in the European Union (EU). By determining measuring ranges, B/B0-50% values, inter- and intra-assay variations and cross-reactions as well as limits of detection (LOD) and recoveries for clenbuterol in bovine urine it could be demonstrated that a number of test kits showed considerable quality defects, reducing their applicability to residue control. LODs for urine assayed without a previous clean-up (as recommended by all kit manufacturers) varied between 1.2 and 11.1 ng clenbuterol per ml urine and did thus not meet the requirement of 1 ng/ml of the official residue control plans of the EU Member States.