Ordering Recommendation

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

New York DOH Approval Status

This test is New York state approved.

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


Quantitative Enzymatic Assay




1-5 days

Reference Interval

Test Number
Reference Interval
  Pseudocholinesterase, Total 2,900-7,100 U/L
  Dibucaine Number Greater than or equal to 80

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.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Compliance Category

Laboratory Developed Test (LDT)


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


CPT Codes

82638; 82480


Component Test Code* Component Chart Name LOINC
0020059 Pseudocholinesterase, Total 2098-2
0020060 Dibucaine Number 39354-6
* 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
Pseudocholinesterase, Dibucaine Inhibition