Cholinesterase, RBC and Plasma (CA Clients)

Test Code

90372

CPT Codes
82480, 82482

Preferred Specimen

5 mL whole blood collected in an EDTA (lavender-top) tube and
1 mL plasma collected in an EDTA (lavender-top) tube

Minimum Volume

4 mL whole blood • 0.5 mL plasma

Other Acceptable Specimens

Plasma collected in: PPT potassium EDTA (white-top) tube

Instructions

Draw two EDTA (lavender-top) tubes of whole blood. Spin one tube to separate plasma. Pour plasma into plastic aliquot tube (label this vial as plasma). Send one 5 mL refrigerated uncentrifuged whole blood (4 mL minimum) and 1 mL refrigerated plasma (0.5 mL minimum). Do not send packed cells. Do not send only one tube of whole blood.
Plasma cholinesterase results, as well as the calculated RBC cholinesterase results, are not accurate if plasma sample is not separated from the RBCs in a timely manner. Hemolyzed plasma samples are not acceptable. Hemolysis can lead to apparent increases in plasma cholinesterase activity, and could mask an enzyme deficiency.

Note: PPT potassium EDTA (white-top) tubes should be centrifuged within 24 hours.

Transport Container

EDTA (lavender-top) tube and transport tube

Transport Temperature

Refrigerated (cold packs)

Specimen Stability

Room temperature: 24 hours
Refrigerated: 7 days
Frozen: Unacceptable

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

Hemolysis • Lipemia • Received room temperature • Received frozen • Receipt of only a single tube of whole blood

Methodology
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.

This test code is for California patient testing. For non-California testing, use test code 338.

Setup Schedule

Sun-Thurs

Limitations

Elevated RBC values, caused by the presence of young RBCs and reticulocytes, may mask acetylcholinesterase inhibition. Plasma 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

Cholinesterase, RBC	9572-15031 IU/L
Cholinesterase, Plasma
Male	3334-7031 IU/L
Female	2504-6297 IU/L

Clinical Significance

True cholinesterase (RBC and plasma) activity is decreased in individuals with exposure to organophosphorous insecticides. True cholinesterase, found in erythrocytes and nerve tissue, is responsible for inactivating acetylcholinesterase at nerve endings. With decreased enzyme activity, patients may display a range of nervous system dysfunction. Analysis of RBC and serum or plasma activity is useful in monitoring exposure and recovery.

Performing Laboratory

Quest Diagnostics Nichols Institute-San Juan Capistrano, CA

33608 Ortega Highway

San Juan Capistrano, CA 92675-2042

Last Updated: November 6, 2024

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.