What is this test?
The name cholinesterase can refer to different enzyme assays. Serum or plasma pseudocholinesterase is commonly used to assess reduced liver synthesis, inherited low activity or exposure to organophosphate or carbamate chemicals; confirm which enzyme and method the laboratory reports.
Why might it be ordered?
- To investigate unexpectedly low cholinesterase activity or prolonged paralysis after certain anaesthetic medicines.
- For clinician-directed assessment after possible pesticide exposure or in selected liver evaluations.
What sample is needed?
A blood sample is required. The laboratory chooses the correct tube and handles the sample for this test.
How should you prepare?
Confirm the assay and tell the clinician about liver disease, pregnancy, medicines, anaesthetic reactions and possible chemical exposure. Suspected organophosphate poisoning with sweating, pinpoint pupils, vomiting, weakness or breathing difficulty is an emergency.
How should you understand the result?
Low serum activity is often the clinically relevant finding, but its cause may be inherited or acquired. The result does not identify a specific exposure without history and other evidence.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.