Ordering Recommendation

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

New York DOH Approval Status

This test is New York state 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


Quantitative Enzyme Multiplied Immunoassay Technique




1-4 days

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