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Pseudocholinesterase (PCHE)

Test Codes

EPIC: LAB7173, Beaker: XMISC, Mayo: PCHE1

Department

Send Outs

Instructions

For cases of prolonged apnea following surgery, wait at least 24 hours before obtaining specimen.

Specimen Collection Criteria

Collect: One Gold-top SST tube.

Also acceptable: One plain Red-top tube.

Physician Office/Draw Specimen Preparation

Centrifuge to separate serum or plasma from cells within two hours of collection. Transfer serum or plasma to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Preparation for Courier Transport

Transport: 1.0 mL serum, refrigerated (2-8°C or 36-46°F). (Minimum: 0.3 mL)

Rejection Criteria

• Hemolyzed specimens.
• Specimen not collected and processed as indicated. 

In-Lab Processing

Centrifuge to separate serum from cells within two hours of collection. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F) within 2 hours of collection.

Transport: 1.0 mL serum, refrigerated (2-8°C or 36-46°F). (Minimum: 0.3 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 24 hours.
Refrigerated (2-8°C or 36-46°F): 14 days.
Frozen (-20°C/-4°F or below): 1 year

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Mayo Clinic Laboratories in Rochester, MN.

Performed

Monday – Friday.
Results available in 2-4 days.

Reference Range

By report.

Test Methodology

Colorimetric Assay.

Interpretation

By report. Pseudocholinesterase is decreased following acute organophosphate poisoning. Use of red cell cholinesterase testing is also recommended for monitoring of organophophate exposure. In patients suspected of having a pseudocholinesterase variant, the Dibucaine Number test is also recommended.

Clinical Utility

Testing for pseudocholinesterase is used to monitor patient exposure to organophosphate insecticides, and aids in the identification of patients with an atypical gene and consequently a low level of cholinesterase that is not inhibited by dibucaine. Patients with this atypical gene are sensitive to the muscle relaxant succinylcholine since they are unable to hydrolyze it rapidly.

Pseudocholinesterase levels are decreased in chronic liver disease (particularly cirrhosis), acute hepatitis, acute infections, pulmonary emboli, chronic renal disease and pregnancy.

CPT Codes

82480

Contacts

Last Updated

7/21/2024