Amniotic Fluid Acetylcholinesterase

Archibald, Angela

doi:10.1016/s0140-6736(81)91948-6

Cited by 6 publications

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“…A low inhibitor concentration might lead to a lower inhibition of both butyrylcholinesterase and acetylcholinesterase, thereby increasing the measured 'acetylcholinesterase' activity (48 -50). Conflicting reports on whether the concentration of amniotic fluid acetylcholinesterase activity is proportional to amniotic fluid volume (51,52) or not (48) might be explained by an error introduced by using acid-solubilized ethopropazine in the sample cuvette only, leading to a decrease in pH of the buffer, overcorrection for non-enzymatic hydrolysis and a tendency to underestimate acetylcholinesterase activity (52). Conflicting reports on whether the concentration of amniotic fluid acetylcholinesterase activity is proportional to amniotic fluid volume (51,52) or not (48) might be explained by an error introduced by using acid-solubilized ethopropazine in the sample cuvette only, leading to a decrease in pH of the buffer, overcorrection for non-enzymatic hydrolysis and a tendency to underestimate acetylcholinesterase activity (52).…”

Section: Technical Considerationsmentioning

confidence: 99%

Reviews

1990

Clinical Chemistry and Laboratory Medicine

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This review discusses the interference in clinical chemical analysis caused by autoantibodies and by antibodies to foreign antigens. The nature of these disturbances, their occurrence, prevalence, and detection, the different ways in which they are manifested, the clinical consequences of the failure to recognize such interference, and finally methods for avoiding these disturbances are discussed.Interference by cold agglutinins in the automatic determination of the erythrocyte count, interference by cryoglobulins in the determination of the leukocyte count, and EDTA-induced thrombocyte agglutination are well documented as sources of error in the analysis of haematological parameters.Enzyme determinations may be affected by the occurrence of macro-complexes of the measured enzyme with immunoglobulins. This type of interference, for example, may occur in the determination of amylase and creatine kinase.Immunoassays for the determination of hormones or tumour markers are sensitive to autoantibodies and heterophilic antibodies. The former are particularly important in the determination of thyroid hormones, where the interference is method-dependent. In several immunoassays, interference by heterophilic antibodies can be abolished by the addition of non-immune serum.Finally, rheumatoid factors, antibodies administered for therapeutic purposes, and monoclonal gammopathies are possible sources of interference in the determination of various analytes.The present discussion presents a selection of impor-Automated cell counting is now an indispensable techtant interfering factors, which can arise in the labo-nique in the determination of haematological paramratory routine, with emphasis on antibodies as the eters. Used routinely, automatic cell counters yield Summary: The concentration of amniotic fluid acetylcholinesterase activity is elevated in cases of foetal open malformations, the levels being higher in cases of open neural tube defects than in cases of abdominal wall defects. Determination of amniotic fluid acetylcholinesterase activity is an established procedure for the antenatal diagnosis of foetal neural tube defects. Performance data, technical advantages and limitations for three procedures for the determination of acetylcholinesterase activity are reviewed in this paper: an immunoassay, a gel electrophoretic procedure and a spectrophotometric procedure. An immunoassay using the monoclonal antibody 4F19 and the gel electrophoretic procedure show nearly identical diagnostic performances, with detection rates for open spina bifida close to 100% and overall false positive rates of approximately 0.2%. The spectrophotometric procedure is not suitable for the antenatal diagnosis of foetal open neural tube defects and abdominal wall defects. It is possible to distinguish open neural tube defects from abdominal wall defects by determination of the ratio of acetylcholinesterase activity to butyrylcholinesterase activity, either by combining the 4F19 immunoassay with a butyrylcholinesterase immunoassay or by gel electr...

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Section: Technical Considerationsmentioning

confidence: 99%