Primidone, Plasma/Serum (Referred Out) - Saskatoon

Overview

Description

Ordering recommendation

• Collect immediately before next oral dose for trough concentration at the steady state

Alias

• Mysoline

Specimen Information

Specimen types accepted

• Serum or plasma

Specimen collection container

• Preferred collection container: Red (non-gel)
• Alternative collection container: Dark Green (non-gel lithium heparin)
• Alternative collection container: Lavender (EDTA)

Required volume

• Optimal volume: 4.0 mL full collection tube
• Minimum volume: 1 mL serum or plasma

(Submitting the minimum volume makes it impossible to repeat the test or perform confirmatory/reflex testing. In some situations, a minimum volume may require a second collection.) 

Transport and stability

• Centrifuge and remove serum from cells as soon as possible

Rejection criteria

• Specimens received where the proper collection protocols were not followed
• Pathology and Laboratory Medicine Acceptance and Rejection Criteria

Performance

Days/times performed

Availability	Shipped daily Monday to Sunday
Testing site	Referred out by St. Paul’s Hospital Laboratory to the Roy Romanow Provincial Laboratory

 

Maximum laboratory time

Results reporting

• One day turnaround time by testing laboratory

Other information

Additional comments

• This test includes both parent drug and metabolite (i.e., phenobarbital)

• Reference values: 

  • Primidone:
    • Therapeutic: 23 - 46 umol/L
    • Toxic: > 115 umol/L
  • Phenobarb:
    • Therapeutic:
    • Toxic: > 216 umol/L

Last Updated: January 9, 2026