Valproic Acid, Free and Total
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.
Submit With Order
ARUP Consult®
Disease Topics
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 NumberComponentsTherapeutic Range
0099308Valproic Acid, TotalTherapeutic Range: 50-125 µg/mL
Toxic: Greater than 150 µg/mL
0099791Valproic Acid, FreeEffective November 18, 2013
Therapeutic Range: 7-23 µg/mL
Toxic: Greater than 30 µg/mL
0099309Valproic Acid, Percent Free5-18 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.

Hotline History
Component Test Code*Component Chart NameLOINC
0099308Valproic Acid, Total4086-5
0099309Valproic Acid, Percent Free32283-4
0099791Valproic Acid, Free4087-3
* 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.
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