RESUMO
PURPOSE: Compliance with post-vasectomy semen analysis could be improved with the availability of a simple, rapid and accurate home test. SpermCheck Vasectomy, a highly sensitive lateral flow immunochromatographic diagnostic device, was designed to detect extreme oligospermia or azoospermia in men after vasectomy. We report the results of clinical and consumer testing of SpermCheck. MATERIALS AND METHODS: A prospective, noncomparative observational study assessed the ability of SpermCheck Vasectomy to predict post-vasectomy sperm counts obtained using a hemacytometer procedure based on standard World Health Organization methodology. Consumer studies evaluated ease of use. RESULTS: A cohort of 144 post-vasectomy semen samples was tested in the clinical trial. SpermCheck was 96% accurate in predicting whether sperm counts were greater or less than a threshold of 250,000 sperm per ml, a level associated with little or no risk of pregnancy. Sensitivity was 93% (95% CI 79% to 98%) and specificity was 97% (91% to 99%). The positive predictive value of the test was 93% (79% to 98%), and most importantly the negative predictive value was 97% (91% to 99%). The test gave a positive result 100% of the time at sperm concentrations of 385,000/ml or greater. Consumer studies with 109 lay volunteers showed that SpermCheck was easy to use. Volunteers obtained the correct or expected test result in every case and the correct response rate on a 20 question survey about the test was 97%. CONCLUSIONS: SpermCheck Vasectomy, a simple and reliable immunodiagnostic test that can provide evidence of vasectomy success or failure, offers a useful alternative to improve compliance with post-vasectomy sperm monitoring. It is currently the only Food and Drug Administration approved test for this purpose.