The effects of contamination on the AChE gel electrophoresis assay used in the diagnosis of NTDs were investigated with amniotic fluids artificially contaminated with FBS, BCS, maternal and fetal blood, respectively.
The amniotic fluids contaminated with FBS showed strong false positive results below 0.5% concentrations and its profile was nearly identical to that of NTDs-specific AChE. Whereas BCS and fetal and maternal plasmas gave negative results at all
concentrations ranging from 5% to 0.5% contaminations.
The water-soluble fraction of maternal erythrocytes and the detergent(Triton X-100)-soluble fraction of both of maternal and fetal erythrocytes were elucidated to contain a significant amount of AChE that illustrated a very heterogeneous pattern
of
fast
moving bands located slightly different positions compared to NTDs-specific AChE It was, thus, suggested that, though the detergent-soluble fraction had little posibility of acting as false positive on considering that normal AChE assay
procedures
exclude any dertergent including Triton X-100, the water-soluble fraction might yield false positive results occasionally unless careful exmination was not taken.
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