Total alpha-fetoprotein and Lens culinaris agglutinin-reactive alpha-fetoprotein in fetal chromosomal abnormalities

Objective To examine the differences in multiples of the median (MoM) of to tal alpha-fetoprotein, and the proportion of Lens culinaris agglutinin reac tive alpha-retoprotein (% alpha-feroprotein-L2 + L3) in the maternal serum and amniotic fluid of pregnant women whose fetuses were diagnosed with auto somal or sex chromosomal abnormalities. Design Prospective consecutive series. Setting University hospital. Sample Maternal sera and amniotic fluids from 46 pregnant women with trisom y 21 fetuses, 10 pregnant women with trisorny 18 fetuses, one pregnant woma n with a trisoiny 13 fetus, six pregnant women with fetal sex chromosomal a bnormalities, and 100 pregnant women for whom the fetal karyotype was diagn osed as normal following a genetic amniocentesis. Results The proportion of alpha-fetoprotein-1-2 + L3 in maternal serum for trisomy 21 (40.3%, P < 0.0001) and trisomy 18 (39.8%, P < 0.05) showed a si gnificantly higher value compared with normal (32.6%). The proportion of al pha-fetoprotein-L2 + L3 in amniotic fluid was significantly higher (P < 0.0 001) for trisomy 21 (46.6%) than for a normal karyotype (41.5%). Only for t he trisomy 21 group was there a strong correlation in the % alpha-fetoprote in-L2 + L3 between maternal serum and amniotic fluid (r = 0.840, P < 0.0001 ). For all groups, there was no correlation between alpha-fetoprotein MoM a nd % alpha-fetoprotein-1-2 + L3 in maternal serum and amniotic fluid. Conclusion The proportion of alpha-fetoprotein-L2 + L3 in maternal serum is an appropriate choice for a trisomy 21 biochemical marker, and it is possi ble that combining alpha-fetoprotein-1-2 + L3 analysis with assays, of alph a-fetoprotein in maternal serum could further improve the sensitivity and s pecificity of multiple marker screening.