title: The efficacy of a serum screening service for neural-tube defects: the South Wales experience.
abstract: Serum-alpha-fetoprotein (AFP) levels were measured in more than 15 000 pregnant women in an investigation designed to examine the operational issues entailed in a large-scale population screening programme for antenatal detection of neural-tube defects. The proportion of open neural-tube defects (ONTD) terminated as a result of serum screening was 56.1% (66.6% for anencephaly and 40.7% for open spina bifida). The principle causes of poor efficacy were: failure of pregnant women to undergo screening (18.2% of ONTD were not screened); failure of the screening test to detect ONTD (20.4% of those screened were below the 90th centile); decisions against termination of detected ONTD (14% of ONTD detected by serum AFP were not terminated). Given present practices and knowledge it is doubtful whether overall efficacy levels above 65% for open spina bifida can be achieved under normal service conditions. The establishment of a regional or national screening programme on grounds of clinical efficacy alone may be premature. The decision would seem to hinge principally around a careful consideration of the economic issues.
mesh_terms: D000757:Anencephaly / Q000097:blood / Q000175:diagnosis / Q000517:prevention & control; D005069:Evaluation Studies as Topic; D005260:Female; D005865:Gestational Age; D006801:Humans; D008403:Mass Screening / Q000592:standards*; D009436:Neural Tube Defects / Q000097:blood / Q000175:diagnosis / Q000517:prevention & control*; D011247:Pregnancy; D037841:Pregnant People; D011296:Prenatal Diagnosis; D018570:Risk Assessment; D016136:Spina Bifida Occulta / Q000097:blood / Q000175:diagnosis / Q000517:prevention & control; D014852:Wales; D000509:alpha-Fetoproteins / Q000032:analysis*
chemical_list: D000509:alpha-Fetoproteins