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Cholinesterase, RBC and Plasma
Test CodeCHOLPROF
Quest Code
338
CPT Codes
82480, 82482
Preferred Specimen
5 mL whole blood collected in an EDTA (lavender-top) and
1 mL plasma collected in an EDTA (lavender-top)
1 mL plasma collected in an EDTA (lavender-top)
Minimum Volume
4 mL whole blood • 0.5 mL plasma
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 RBC's 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.
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 RBC's 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.
Transport Temperature
Refrigerated (cold packs)
Specimen Stability
Room temperature: 24 hours
Refrigerated: 7 days
Frozen: Unacceptable
Refrigerated: 7 days
Frozen: Unacceptable
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Hemolysis
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.
Setup Schedule
Set up: Tues-Sat; Report available: Next day
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 |
| 14225 Newbrook Drive |
| Chantilly, VA 20153 |
Last Updated: October 1, 2017
