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Test Code BLOD0533 Valproic Acid (Depakote), Plasma or Serum

Useful For

Anti-epileptic drug monitoring


Particle-Enhanced Turbidimetric Inhibition Immunoassay (PETINIA)

Performing Laboratory

Bozeman Health Laboratory Services

Specimen Requirements

Specimen Type: Plasma or serum
Container/Tube: Light-green top (lithium heparin gel), red top, or gold top
Specimen Volume: 1 mL
Specimen Minimum Volume: 0.5 mL

Collection Instructions:

1. Specimen for a peak level should be drawn 1 to 3 hours after administration of dose.
2. Specimen for a trough level should be drawn immediately prior to next dose.

3. Spin down within 2 hours of draw, remove plasma or serum from cells.

4. Label specimen as plasma or serum.

Additional Information:

1. Draw time is only a recommendation. Specific circumstances related to an individual patient, eg, renal function, hepatic function, concurrent medications, signs or symptoms of toxicity, and/or therapeutic response may necessitate individualization of drawing schedules.
2. Date and time of last dose, date and time of draw, and plasma are required.

Specimen Transport Temperature


Specimen Stability


Specimen Type Temperature Time
Plasma or Serum Ambient 2 hours
  Refrigerated 8 hours
  Frozen 2 months


Reference Values

Therapeutic concentration: 50-100 µg/mL

Toxic concentration (automatic call-back): >120 µg/mL


Therapeutic valproic acid concentrations vary significantly depending on the individual patient. A therapeutic range of 50 µg/mL to 100 µg/mL (346-693 µmol/L) may indicate effective serum concentration for many patients; however, some individuals are best treated at concentrations outside this range. The physician must determine the appropriate therapeutic range for each patient.

Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding