Evaluation and comparison of commercially available pregnancy tests based on monoclonal antibodies to human choriogonadotropin.

We evaluated eight pregnancy tests: Tandem Icon, beta-hCG Rapid, Pregnastick (immunoenzymometric assays), Neo-Pregnosticon (direct hemagglutination), Pregnospia (sol particle immunoassay), Neo-Planotest (latex agglutination), Gravindex beta-hCG, and beta-hCG Slide Test (both latex-agglutination inhibition), all of which detect human choriogonadotropin (hCG) in urine. We investigated the limits of detection and the responses to the following substances: human lutropin, protein, and blood, and high concentrations of hCG. Using 100 patients' samples, we assessed the diagnostic specificity and sensitivity as well as the accuracy of each kit. The detection limits for Tandem Icon, beta-hCG Rapid, Neo-Pregnosticon, Pregnospia, Neo-Planotest, and Gravindex beta-hCG were as stated by the manufacturers. Only Neo-Planotest gave a false-positive result for lutropin. The three immunoenzymometric assays were not affected by protein or blood, but of these only Tandem Icon did not exhibit prozoning. The five other kits gave false-positive or false-negative results for protein and blood. Tandem Icon performed best, being quick and easy to use and without susceptibility to interfering substances.