Pseudocholinesterase, scoline sensitivity,
To confirm the diagnosis of Anectine (suxamethonium chloride)
and mivacron (Mivacurium) apnoea after anaesthetic.
To determine phenotype of patients with low serum Cholinesterase
Patients with an abnormal phenotype should have family studies
performed, and if sensitive to Scoline should be issued with a
Patients with ?organophosphorus poisoning can also have serum
levels measured but red cell acetylcholinesterase can also be
Susceptibility to 'Scoline apnoea' is inherited as an autosomal
dominant disorder; cholinesterase activity is usually, but not
always, low. Dibucaine and fluoride numbers improve the sensitivity
and specificity of the test.
Family studies should be done on patients found to be sensitive so
that other affected individuals can be cautioned against exposure
to suxamethonium or mivacurium.
For further useful information about cholinesterase follow
Total cholinesterase, dibucaine, fluoride and RO numbers,
Request on ICE
Analysed by referral laboratory if specific criteria met.
Investigation of suspected scoline sensitivity, prolonged apnoea
following suxamethonium (Scoline) or mivacurium. Part of family
Do not take samples during apnoea or within 24
hours of suxamethonium administration. If FFP or
cholinesterase preparations have been given, then wait 6
weeks before taking sample.
SST Serum AND Biochemistry EDTA sample
Sent to referral laboratory
Causes for Rejection
Unlabelled or incorrectly labelled sample; not meeting specific
criteria for analysis; inadequate clinical information.
Total Cholinesterase: 3,700 - 11,500 IU/L.
Normal phenotype is UU.
Scoline-sensitive phenotypes are AA, AK, and KK.
Heterozygotes are not usually sensitive but scoline sensitivity
may increase during pregnancy, and total levels may also be
For sensitive individuals a sensitivity card should be enclosed
with the result. This is sent to the clinician concerned together
with a covering letter
Low levels are also found in pregnancy and in patients with
hepatocellular disease. Organophosphate poisoning reduces the
activity of this enzyme, making it useful for the detection of
poisoning. Red cell cholinesterase may also be required for the
diagnosis of poisoning with organophosphate or carbamate
insecticides and monitoring of long term exposure.