Preferred Specimen:
- 5 ml whole blood collected in an EDTA (lavender-top) tube
- 1 ml plasma collected in an EDTA (lavender top) tube
- 1 ml serum
Minimum Volume:
- 4 mL whole blood
- 5 mL plasma
- 5 mL serum
Alternative Specimen(s): Whole blood and plasma collected in: Sodium heparin (green-top) tubes
Collection Instructions Transfer plasma and serum to plastic transport tubes and send refrigerated with whole blood
Transport Container: EDTA (lavender-top) tube and plastic screw-cap vials
Transport Temperature: Refrigerated (cold packs)
Specimen stability:
- Room temperature: 24 hours
- Refrigerated: 7 days
- Frozen: unacceptable
Reject Criteria:
- Hemolysis
- Lipemia
- Received room temperature
- Received frozen
Methodology: Kinetic Spectrophotometric(KS)
Limitations: 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(s)
| Cholinesterase, Serum | |
| Male | 3342-7586 IU/L |
| Female | 2673-6592 IU/L |
| 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.