Abstract # H-07

PostApproval Study of Alphafetoprotein (AFP) Test Kits for Fetal NeuralTube Defects (NTDs): Some Epidemiological Aspects. K.J. Fugate, Ph.D.1, D. Marinac Dabic, M.D.2, R. Daley, D.V.M., M.P.H.1 and SriKrisna Vadlamudi, D.V.M., Ph.D.1.   CDRH 1Office of Device Evaluation, Division of Clinical Laboratory Devices, 2Office of Surveillance and Biometrics,Division of Biometrics

The reported prevalence of anencephaly and spina bifida (NTDs) in the United States has steadily declined since the late 1980s. The impact of the prenatal detection and subsequent pregnancy termination on the reported prevalence of anencephaly and spina bifida in the U.S. has not been well established. This study represents a collaborative effort of five manufacturers of the AFP test kits and the FDA to assess the performance of the kits and the impact of the testing on the prevalence of the NTDs. A total of 29,712 pregnant women from 25 testing centers were enrolled into the study. The sensitivity of the MSAFP test was 91.7%; specificity 96.0% and the positive predictive value 3.6%. The AFAFP test of the amniotic fluid had a sensitivity of 100%; specificity of 98.0% and the positive predictive value of 73.1%. The prevalence of the NTDs (per 1000 pregnancies) was 1.64 CI (0.982.30). Out of 24 pregnancies with an NTD outcome, 6 were carried to term while 12 and 6 were terminated as elective and spontaneous abortions respectively.