Cholinesterase, Serum, with Dibucaine Inhibition

Test Code

CPT Codes
82480, 82638

Preferred Specimen
1 mL serum

Minimum Volume
0.5 mL



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?)
Gross hemolysis • Moderate hemolysis • Light hemolysis

Kinetic Spectrophotometric (KS)

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

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

Reference Range
Cholinesterase, Serum  
  Male 3342-7586 IU/L
  Female 2673-6592 IU/L
Dibucaine Number 81.6-88.3 % Inhibition

Cholinesterase with Dibucaine Inhibition
Phenotype % Inhibition


A* 19.9
AS* 20.7
S1* 5.3
S2* 67.6
F* 71.8
AF* 60.2
FS* 76.7
UA 72.7
UF 79.8
US 84.4
* Phenotype reportedly associated with prolonged apnea.

Clinical Significance
The Pseudocholinesterase phenotype can be determined by analysis of Pseudocholinesterase and the percent inhibition by Dibucaine. Approximately 96% of the population has normal activity, approximately 4% will exhibit decreased activity that leads to prolonged paralysis following use of succinylcholine, and 1 in 3000 patients will exhibit severe, prolonged paralysis following anesthetic exposure.

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

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.