Cholinesterases: Acetylcholinesterase, Pseudocholinesterase and Dibucaine Number


Cholinesterase: CHS; Acetylcholinesterase: AcCHS, RBC or red blood cell cholinesterase, erythrocyte cholinesterase, true cholinesterase; Pseudocholinesterase: PCHE.

To assess for acquired or inherited pseudocholinesterase deficiency.

Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction.

Normal Findings
Method: Spectrophotometry, kinetic.

TestConventional Units
Acetylcholinesterase (AcCHS)/RBC cholinesterase25–50 U/g Hgb
TestConventional Units
Pseudocholinesterase (PCHE)
  Males3,334–7,031 units/L
  Females2,504–6,297 units/L
Dibucaine NumberFraction (%) of Activity Inhibited
Normal homozygote79%–84%
Abnormal homozygote16%–28%

Critical Findings and Potential Interventions

  • A positive PCHE result indicates that the patient is at risk for prolonged or unrecoverable apnea related to the inability to metabolize succinylcholine. Notify the anesthesiologist if the test result is positive and surgery is scheduled.

Timely notification to the requesting health-care provider (HCP) of any critical findings and related symptoms is a role expectation of the professional nurse. A listing of these findings varies among facilities.

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