Cholinesterase, Plasma [335]

For Specimen Integrity during Extreme Weather see the “Lockbox Usage in Extreme Weather” document at the top of this page.

Test Code

Alias/See Also

CPT Codes

Preferred Specimen
1 mL plasma collected in an EDTA (lavender-top) tube

Minimum Volume
0.5 mL

Other Acceptable Specimens

Draw a lavender-top (EDTA) tube of whole blood. Spin tube to separate plasma. Pour plasma into plastic aliquot tube and refrigerate until shipping. Ship plasma sample refrigerated. Do not send packed cells. Do not send one tube of whole blood.

Plasma cholinesterase results are not accurate if plasma sample is not separated from RBC's in a timely manner (within 1 hour). Hemolyzed plasma samples are not acceptable. Hemolysis can lead to apparent increases in plasma cholinesterase activity, and could mask an enzyme deficiency.

Transport Container
Plastic screw-cap vial

Transport Temperature
Refrigerated (cold packs)

Specimen Stability
Room temperature: 21 days
Refrigerated: 21 days
Frozen: 30 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Kinetic Spectrophotometric (KS)

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule
Set up: Mon-Fri; Report available: Next day

Results may be depressed in patients who consume oral contraceptives. Hepatic disease may cause up to a 70% decrease in enzyme levels. Cholinesterase may be slightly elevated in patients with obesity or diabetes.

Reference Range
Male 3334-7031 IU/L
Female 2504-6297 IU/L

Clinical Significance
Approximately 1 in every 2500 individuals has inherited defective or deficiency of the enzyme (pseudocholinesterase) that metabolizes succinylcholine (an anesthetic agent). With "normal" dosage, these individuals have prolonged apnea. Such individuals are responsive at much smaller concentrations of this anesthetic agent than the general population. Low concentrations of pseudocholinesterase are observed in individuals exposed to organophosphorous insecticides and patients with hepatic dysfunction.

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153

Last Updated: November 29, 2021

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.