Ordering Recommendation

Preferred test for therapeutic drug management in patients with renal failure or conditions that may alter albumin concentrations.


Quantitative Enzyme Multiplied Immunoassay Technique




1-4 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation

Timing of specimen collection: Pre-dose (trough) draw - At steady state concentration.


Plain red.

Specimen Preparation

Separate serum from cells within 2 hours of collection. Transfer 2 mL serum to an ARUP Standard Transport Tube. (Min: 1 mL)

Storage/Transport Temperature


Unacceptable Conditions

Light blue (citrate), gray (oxalate), green (heparin), K2EDTA plasma, tubes that contain liquid anticoagulant, or gel separator tubes.


After separation from cells: Ambient: 24 hours; Refrigerated: 1 week; Frozen: 1 month

Reference Interval

Test Number Components Therapeutic Range
0099308 Valproic Acid, Total Therapeutic Range: 50-125 µg/mL
Toxic: Greater than 150 µg/mL
0099791 Valproic Acid, Free Effective November 18, 2013
Therapeutic Range: 7-23 µg/mL
Toxic: Greater than 30 µg/mL
0099309 Valproic Acid, Percent Free 5-18 percent

Interpretive Data

Free valproic acid may be important to monitor in patients with altered or unpredictable protein binding capacity because valproic acid exhibits variable, dose-dependent protein binding. Valproic acid is also subject to drug-drug interactions due to displacement of protein binding.  Calculating percent free attempts to minimize differences in test cross-reactivity and may be useful in dose optimization. Adverse effects may include headache, somnolence and dizziness.

Compliance Category



Hotline History


CPT Codes

80164; 80165


Component Test Code* Component Chart Name LOINC
0099308 Valproic Acid, Total 4086-5
0099309 Valproic Acid, Percent Free 32283-4
0099791 Valproic Acid, Free 4087-3
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • Depacon
  • Depakene, Free
  • Depakote, Free
  • Dipropylacetic Acid
  • Eplim
  • Free Valproate
  • Free Valproic Acid
  • Free VPA
  • Orlept
  • Protein Free Valproic Acid
  • Stavzor, Free
  • Valproate
  • valproic acid blood level
  • VPA blood level
Valproic Acid, Free and Total