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UW Health SMPH
American Family Children's Hospital

UW Hospital and Clinics Lab Test Directory

Test Name: Valproate

Test Code(s): VATE / DEP

CPT Code(s): 80164

Methodology: Particle Enhanced Turbidometric Inhibition Immunoassay (PETINIA)

Clinical Significance: Anticonvulsant

Days Performed: Daily, 24 hours.

Turnaround Time: Stat: 1 hour.
Routine: 4 hours.

Specimen Requirements

Specimen: Blood

Collection Instructions: Collect specimen for trough level prior to next dose.

Collection Container: Preferred: Red top

Collection Volume: Preferred: 2 mL
Pediatrics: 0.4 mL

Sample Analyzed: Serum

Volume Required: Preferred: 1 mL
Pediatrics: 0.2 mL

Specimen Processing: Centrifuge.  Transfer cell-free serum to plastic vial.  Refrigerate.

Specimen Transport: Transport specimen to UWHC Core Laboratory (B4/220). Transport with coolant pack if coming from outreach location.

Unacceptable Criteria: Specimens collected in red cap with yellow ring (SST) tubes are not acceptable.

Stability: Ambient: 2 hours on cells
Refrigerated: 8 hours
Frozen: Up to 2 months


Generally effective therapeutic concentration: 50-125 mcg/mL


There is an increased incidence of side effects seen at concentration greater than 130 mcg/mL.

Critical Calls: View

Additional Information:

Result of "BELOW" indicates that the concentration is below the method detection limit of 3.0 mcg/mL. The half-life of valproate is approximately 8-12 hours. Peak concentrations occur 0.5-2 hours after administration of capsules or syrup; 3-8 hours after enteric coated tablets. The drug is primarily metabolized in the liver and is excreted as the glucuronide conjugate in the urine. Valproate is generally considered to be an enzyme inhibitor. Concurrent administration may result in increased carbamazepine-10,11-epoxide, ethosuximide, phenobarbital, and unbound phenytoin concentrations. Concurrent administration with enzyme inducing drugs may cause marked decrease in valproate half-life and plasma concentrations.

Depakote Depakene
Valproic Acid

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