ALPHA-FETOPROTEIN AND ACETYLCHOLINESTERASE ACTIVITY IN FIRST-TRIMESTER AND EARLY 2ND-TRIMESTER AMNIOTIC-FLUID

Normal ranges of amniotic fluid alpha-fetoprotein (AFP) and acetylchol inesterase activity (AChE) are described for gestational weeks 11-14 u sing rocket gel immunoelectrophoresis for AFP quantitation and a monoc lonal antibody (4F19) enzyme antigen immunoassay for AChE activity mea surement. The normal ranges were established by the examination of 281 amniotic fluid samples from 281 normal pregnancies. AFP was found to increase from a median level of 14.0 MIU/l at 11 weeks to a maximum at 13 weeks (median = 18.0 MIU/l) (P<0.05), thereafter falling (not sign ificant). No AChE test result exceeded 4.8 nkat/l. In addition, AFP an d AChE values for three cases of fetal malformation, identified by the biochemical analyses of amniotic fluid, are given. These cases includ ed two fetuses with a neural tube defect and one fetus with an abdomin al wall defect. Amniocentesis was performed at 10, 11, and 14 weeks, r espectively. The AFP and AChE values were all high.