Unit Code 8522:
Acetylcholinesterase, Erythrocytes
Useful For
Detecting effects of remote (months) past exposure to
organophosphatase inhibitors (insecticide poisoning)
Clinical Information
Acetylcholinesterase (AChE) is anchored to the external surface
of the red blood cell. Its appearance in a lysate of red cells is
diminished in paroxysmal nocturnal hemoglobinuria (PNH). The
use of red cell AChE for PNH has not gained widespread acceptance,
and flow cytometry testing is most often used for PNH (see #81156
"PI Linked Antigen, Blood").
Red cell AChE is most often used to detect past exposure to
organophosphate insecticides with resultant inhibition of the enzyme.
Both the pseudocholinesterase activity in serum and red cell AChE
are inhibited by these insecticides, but they are dramatically different
vis-a-vis the temporal aspect of the exposure. The half-life of the
pseudo-enzyme in serum is about 8 days, and the "true" cholinesterase
(AChE) of red cells is over 3 months (determined by erythropoietic
activity). Prior exposure up to several weeks is determined by assay
of the pseudo-enzyme and months after exposure by measurement
of the red cell enzyme. The effect of the specific insecticides may be
important to know prior to testing.
Reference Values
26.7-49.2 U/g of hemoglobin
Interpretation
Activities less than normal are suspect for exposure to certain
insecticides.
Cautions
Make sure the potential offending agent is, indeed, an AChE
inhibitor.
Pseudocholinesterase acitivity in serum is the appropriate test
for succinylcholine sensitivity to anesthesia.
Clinical Reference
Robinson DG, Trites DG, Banister EW: Physilogical effects of work
stress and pesticide exposure in tree planting by British Columbia
silviculture workers. Ergonomics 1993;36:951-961
Fuortes LJ, Ayebo AD, Kross BC: Cholinesterase-inhibiting
insecticide toxicity. Am Fam Phys 1993;47:1613-1620
External
link
PDF
document
Excel
document
Word
document