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False positive gel‐acetylcholinesterase results in blood‐stained amniotic fluids
Author(s) -
BARLOW ROBERT D.,
CUCKLE HOWARD S.,
WALD NICHOLAS J.,
RODECK CHARLES H.
Publication year - 1982
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/j.1471-0528.1982.tb05033.x
Subject(s) - amniotic fluid , acetylcholinesterase , fetus , contamination , aché , medicine , andrology , chromatography , obstetrics , chemistry , pathology , physiology , pregnancy , biology , biochemistry , enzyme , ecology , genetics
Summary. The effect of blood contamination on the gel‐acetylcholinesterase (AChE) test used in the diagnosis of fetal open neural‐tube defects was studied with amniotic fluid samples artificially contaminated with fetal or maternal blood in concentrations covering a range exceeding that usually found in clinical practice. Amniotic fluid samples contaminated with maternal blood gave negative gel‐AChE results at all concentrations. Contamination with fetal blood yielded positive results if the erythrocyte concentration was greater than about 60 × 10 6 cells/ml. Thus contamination of amniotic fluid with blood is only likely to cause false positive gel‐AChE results if this critical concentration is exceeded. Such samples will occur only rarely in clinical practice but when they do the diagnosis should be made with caution.