[Significance and limits of alpha-fetoprotein levels in the prenatal diagnosis of malformations of the central nervous system].

Amniotic fluid or/and serum alpha-foeto protein (AFP) determination is used as a test-system for screening of neural tube defects. The physiologic basis of this screening are described taking into account the evolution of AFP concentration in foetal and maternal blood, and in amniotic fluid. As for all the biologic screening systems, the acquired experience reveals a lack of sensibility and specificity. First the authors analyse the analytic and biologic problems which have an effect upon sensibility; then, they consider the mechanisms which explain the specificity lack showing itself in some foetal malformations. Practically, interpretation of AFP results requires necessarily familial story and echography results. Taking into consideration the different problems concerning AFP, a programme to utilize the test-system is presented for prenatal diagnosis of malformations of central nervous system.