Cholinesterase Phenotype

Immunology

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Description

Suxamethonium apnoea is a rare disorder that occurs when a patient has a deficiency of cholinesterase. The majority of cases are found to have a genetic abnormality, but the defect in cholineasterase production can also be spontaneous [3]. Cholinesterase metabolises suxamethonium. When suxamethonium is given as a muscle relaxant prior to surgery the patient is unable to metabolise suxamethonium efficiently and they remain paralysed and unable to breathe for much longer than expected after surgery [1,3]. Blood tests measure total cholinesterase activity, and enzyme phenotyping can also be performed. If enzyme levels are reduced or low normal, or there is an abnormal or silent phenotype it will be recorded in the patient notes. The patient will be given a medical warning card that should be shown before any future surgery. Direct family members should also be asked to have cholinesterase studies [2].

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Indications

Investigation of suxamethonium apnoea.

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Sample Type

2mL Serum (Gel 5mL Yellow tube) or 2mL Plasma (EDTA or Heparin).
Requests from outside Sheffield: transport at ambient temperature via Royal Mail or Courier.

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Reference Range

Reference range on report.

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Turnaround Time

Within 3 weeks

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Testing Frequency

Weekly (send away test).

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References

Calvey N. Adverse drug reactions. Anaesthesia and intensive care medicine. 2005. 6(7):245-249. [Ref 1]
Rees JE. Suxamethonium apnoea. Update in Anaesthesia. 2005. 19:16. [Ref 2]
Morgan AA. Apnoea following suxamethonium: The genetic study of four generations of a family. Journal of Medical Genetics. 1982. 19:22-25. [Ref 3]

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Please note: the above information is subject to change and we endeavour to keep this website up to date wherever necessary.