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Alternate test name


Lab area
Clinical Biochemistry - TDM & Toxicology
Method and equipment
Expected turn-around time
Stat: 3 hours Routine: 72 hours
Specimen type


Plasma (Heparin or Citrate)

Specimen requirements

100 uL

Storage and transportation
  • Serum/plasma must be separated within 2 hours of collection
  • Store and ship frozen
Shipping information
The Hospital for Sick Children
Rapid Response Laboratory
555 University Avenue, Room 3642
Toronto, ON
M5G 1X8
Phone: 416-813-7200
Toll Free: 1-855-381-3212
Hours: 7 days/week, 24 hours/day
Background and clinical significance
Primidone is an anticonvulsant drug used primarily in the treatment of complex partial seizures and their secondary generalizations. Primidone is metabolized primarily in the liver. The major metabolite, phenylethylmalonamide has little anticonvulsant activity. The second metabolite, phenobarbital has potent anticonvulsant activity. Due to its long half life, patients on long term primidone therapy should also have the phenobarbital quantitation done along with the primidone. Primidone toxicity may occurr in patients with renal disease. Typical toxic symptoms may include confusion, dizziness, nystagmus and ataxia.
Disease condition


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