Valproic Acid, Free and Total
Also known as: VPA-F
Use
This test is preferred for therapeutic drug management in patients with renal failure or conditions that may alter albumin concentrations. Monitoring free valproic acid is crucial in cases of altered or unpredictable protein binding capacity due to variable, dose-dependent protein binding and potential drug-drug interactions. Calculating percent free helps minimize differences in test cross-reactivity and aids in dose optimization. Adverse effects like headache, somnolence, and dizziness may occur.
Special Instructions
Not provided.
Limitations
The test may not accurately reflect concentrations in patients with extremely abnormal protein binding or in those with significant drug-drug interactions affecting protein binding. Free valproic acid measurements should be interpreted in context with clinical findings.
New York Approved
Methodology
Immunoassay (EIA)
Biomarkers
Valproic Acid, Free
AnalyteValproic Acid, Percent Free
AnalyteValproic Acid, Total
Analyte
LOINC Codes
- 4086-5 - Valproate SerPl-mCnc
- 32283-4 - Valproate Free MFr SerPl
- 4087-3 - Valproate Free SerPl-mCnc
Result Turnaround Time
1-4 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
2 mL
Minimum Volume
1 mL
Container
ARUP standard transport tube
Collection Instructions
Separate serum from cells within 2 hours of collection and transfer to transport tube.
Patient Preparation
Predose (trough) draw at steady-state concentration.
Storage Instructions
Refrigerated.
Causes for Rejection
Light blue (citrate), gray (oxalate), green (heparin), K2EDTA plasma, tubes with liquid anticoagulant, or gel separator tubes.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 24 hours |
| Refrigerated | 1 week |
| Frozen | 1 month |
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