Lab Test

Valproic Acid Level

Depakene®, Depakote®, Valproate, Valproex®, Valproic Acid Level, Serum

Test Codes

EPIC: LAB5429, Beaker: VALPA, Antrim: 17139



Specimen Collection Criteria

Collect (preferred specimen): One plain Red-top tube. (Minimum Whole Blood: 1.0 mL)

Also acceptable (not preferred):
 One Gold-top SST tube.

Time of Collection: Trough, just prior to the next dose.

Record the exact time of specimen collection on the tube or in the computer system.

Physician Office/Draw Specimen Preparation

Let specimens clot 30-60 minutes and refrigerate (2-8°C or 36-46°F) the collection tube within two hours of collection. (Minimum: 1.0 mL blood)

Preparation for Courier Transport

Transport: Collection tube, refrigerated (2-8°C or 36-46°F). (Minimum: 1.0 mL blood)

Rejection Criteria

Severely lipemic or hemolyzed specimens.

In-Lab Processing

Let specimens clot 30-60 minutes. Centrifuge specimen to separate serum from cells. Deliver an aliquot of serum or the collection tube immediately to the appropriate testing station.


Specimen Stability for Testing:

Collection Tubes
Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 3 months

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days


Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory
Grosse Pointe Chemistry Laboratory
Royal Oak Toxicology Laboratory
Taylor Chemistry Laboratory
Trenton Chemistry Laboratory
Troy Chemistry Laboratory
Wayne Chemistry Laboratory 


Sunday – Saturday, 24 hours a day.
STAT results available within 1 hour of receipt in the Laboratory.
Routine results available within 24 hours.

Reference Range

Patients Less than 15 Years Old
Pediatric Range: 50-150 mcg/mL.
Critical Range: Greater than 200 mcg/mL.

Patients Greater than 15 Years Old
Therapeutic Range:
50-100 mcg/mL.
Critical Range: Greater than 150 mcg/mL.

Test Methodology

Particle Enhanced Turbidimetric Inhibition Immunoassay.


Valproic Acid is susceptible to concentration-dependent plasma protein binding. Increases in plasma or serum concentrations will likely result in increased drug clearance. Valproic Acid will also compete for plasma protein binding sites and has been shown to decrease the binding of other highly bound drugs. Valproic Acid may inhibit the oxidative metabolism of co-administered medications.

Clinical Utility

Valproic acid is a broad-spectrum anticonvulsant drug used alone to treat simple and complex absence seizures and in combination with other anticonvulsant drugs for control of generalized seizures that include absence seizures. This assay is used to monitor the therapeutic drug level and evaluate the toxicity of valproic acid.

CPT Codes



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