Quantitative estimation of the density ratios of cholinesterase isoenzyme bands in human amniotic fluid in the prenatal diagnosis of malformed fetus

By quantitative estimation of the density ratios of cholinesterase (ChE) isoenzyme bands, we have analysed 100 cases of normal amniotic fluid, and 31 cases of amniotic fluid with malformed fetus. In order to distinguish amniotic fluid with blood contamination from that with non-contamination, blood contaminated amniotic fluid has been assayed at the same time. The results show that 1) the amniotic fluid with blood contamination has five more bands of ChE isoenzyme than that with non-contamination; 2) the ChE isoenzyme band 3/2 density ratios of amniotic fluid with blood contamination and with multimalformation, omphalocele, encephalocele are all ≤S 0.089. These ratios in normal single and twins fetal amniotic fluid are all zero; while those in anencephaly or anencephaly plus spina bifida are all ≥0.11. Therefore, according to the above results we can not only identify the blood contaminated samples but also diagnose and distinguish various forms of malformed fetus.