Ordering Recommendation

Optimize drug therapy and monitor patient adherence; the active metabolite of primidone is phenobarbital.

Mnemonic
PRIM
Methodology

Immunoassay

Performed

Sun-Sat

Reported

Within 24 hours

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect

Plain red. Also acceptable: Green (sodium heparin).

Specimen Preparation

Allow specimen to clot completely at room temperature. Separate serum from cells within 2 hours of collection. Transfer 1 mL serum or plasma to an ARUP Standard Transport Tube. (Min: 0.8 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions

Separator tubes.

Remarks
Stability

After separation from cells: Ambient: 1 week; Refrigerated: 1 week; Frozen: 1 month

Reference Interval
Test Number
Components
Reference Interval
0090230 Phenobarbital 0-2 months: 15.0-30.0 µg/mL
  Toxic: 40.1 µg/mL or greater 
3 months and older: 15.0-40.0 µg/mL
  Toxic: 50.1 µg/mL or greater
  Primidone (Mysoline) 5-12 µg/mL

Interpretive Data

Primidone concentrations greater than 15 µg/mL in conjunction with therapeutic levels of phenobarbital may be associated with toxicity.

Compliance Category

FDA

Note
Hotline History
N/A
CPT Codes

80188; 80184

Components
Component Test Code* Component Chart Name LOINC
0090230 Phenobarbital 3948-7
0090240 Primidone (Mysoline) 3978-4
* 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.
Aliases
  • Luminal
  • Mysoline
  • Mysoline Primidon)
  • Phenobarbital
  • Primidone
Primidone and Metabolite