Pseudocholinesterase, Dibucaine Inhibition
Ordering Recommendation

Order to detect increased sensitivity in individuals who experience prolonged paralysis following succinylcholine or mivacurium administration.

Quantitative Enzymatic
1-5 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
Specimen must be drawn prior to surgery or more than two days following surgery. Do not draw in recovery room. 
Serum separator tube, green (sodium or lithium heparin), lavender (EDTA), or pink (K2EDTA). 
Specimen Preparation
Allow specimen to clot completely at room temperature. Separate serum or plasma from cells ASAP or within 2 hours of collection. Transport 1 mL serum or plasma. (Min: 0.25 mL) 
Storage/Transport Temperature
Unacceptable Conditions
Lt. blue (sodium citrate) or gray (oxalate/fluoride). Whole blood. 
Ambient: 4 hours; Refrigerated: 1 week; Frozen: 3 months 
Reference Interval
Effective November 13, 2017
Test Number
Reference Interval
0020167Pseudocholinesterase, Total2,900-7,100 U/L

Interpretive Data
The dibucaine number (DN) is the percent of pseudocholinesterase (PChE) enzyme activity that is inhibited by dibucaine. Together, the DN and the PChE enzyme activity results can help to identify individuals at risk for prolonged paralysis following the administration of succinylcholine. Decreased PChE enzyme activity in conjunction with a DN less than 30 suggests high risk for prolonged paralysis. Normal to decreased PChE enzyme activity in conjunction with a DN 30-79 suggests variable risk. Although decreased PChE activity in conjunction with DN greater than or equal to 80 suggests variable risk, these results may be caused by exposure to organophosphates, the presence of liver disease, pregnancy, or circulating succinylcholine. Specimens should be collected 48 hours after the administration of succinylcholine.

Compliance Statement B: For laboratory developed tests not using a RUO kit, and for FDA approved, cleared or 510(k) exempt assays with alterations. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

Patients with acute or chronic liver disease, organophosphate poisoning, chronic renal disease, in late stages of pregnancy, or on estrogen therapy may have markedly decreased PChE activities.
Hotline History
View Hotline History
Component Test Code*Component Chart NameLOINC
0020059Pseudocholinesterase, Total2098-2
0020060Dibucaine Number39354-6
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
  • Butyrylcholinesterase
  • Cholinesterase
  • Cholinesterase, Serum
  • Dibucaine
  • Dibucaine Inhibition
  • Dibucaine Number
  • Serum Cholinesterase
  • Serum Pseudocholinesterase