Cholinesterase Studies

Chemical Pathology

Notes

• Plasma cholinesterase (also known as pseudocholinesterase or butyrylcholinesterase/ BChE) is an enzyme essential for the breakdown of acetylcholine, a substance critical for transmission of nerve impulses.
• BChE deficiency can result in temporary paralysis after being given the muscle relaxant suxamethonium (also known as succinylcholine) as part of an operative procedure. This is referred to as ‘suxamethonium apnoea’.
• BChE phenotyping is indicated in patients with suspected suxamethonium apnoea.
• BChE deficiency is inherited in an autosomal recessive manner and individuals should be tested if a first degree relative has experienced suxamethonium apnoea. This normally requires referral to a clinical geneticist.
• Cholinesterase studies may occasionally also be required in individuals who work in the agricultural or organic chemical industry and who may have experienced exposure to organic phosphorus insecticides. Ideally, an initial sample should be taken prior to any exposure to determine the individual’s baseline activity.
• Genotyping may also be performed if clinically indicated.

Sample requirements

Samples should be collected 24 hours post suxamethonium dose to avoid false positives and when patients have recovered and are breathing unaided.

For adults and children blood taken into a 4mL EDTA tube

Storage/transport

Do not store. Send at ambient temperature to the laboratory on the same day as sample collection.

Required information

Relevant clinical details, for example dates of any planned operations, details of any suspected previous reaction, any family history or details of exposure to organophosphates.

Turnaround times

Samples are sent for analysis to a referral laboratory with results expected back within 5 weeks for initial phenotyping.

Reference range

All reports are issued with interpretative comments and an assessment of risk (of suxamethonium sensitivity) based on the phenotype and enzyme activity.

Warning cards are issued for patients likely to be sensitive to suxamethonium and recommendations given with the report on the need for family studies.

Further information

To learn more about cholinesterase studies visit Lab Tests Online

Page last updated 15/03/2024