Valproic Acid, Free and Total, Serum
Use
This test is useful for monitoring both total and free valproic acid levels in patients undergoing therapy. It is also instrumental in assessing patient compliance with prescribed valproic treatment and evaluating potential toxicity. Valproic acid, either alone or with other antiepileptic agents, is effective for treating absence seizures, generalized tonic-clonic seizures, and partial seizures. Monitoring free valproic acid is crucial when other highly protein-bound drugs are co-administered, or in conditions like hypoalbuminemia, pregnancy, kidney or liver failure, as these conditions can increase the free fraction of the drug, directly impacting neurologic activity and toxicity.
Special Instructions
When ordering this test manually, complete and send a Therapeutics Test Request (T831) with the specimen.
Limitations
Specimens subjected to conditions causing protein denaturation, such as significant heat exposure, can falsely increase free valproic acid levels. Timing of specimen collection relative to dosing is crucial as valproic acid concentrations can significantly fluctuate, necessitating sometimes both peak and trough measurements for accurate therapeutic monitoring.
New York Approved
Methodology
Immunoassay
Biomarkers
LOINC Codes
- 57775-9
- 4086-5
- 4087-3
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
2 mL
Minimum Volume
1 mL
Container
Plastic vial
Collection Instructions
Serum gel tubes should be centrifuged within 2 hours of collection. Red-top tubes should be centrifuged, and the serum aliquoted into a plastic vial within 2 hours of collection.
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 72 hours |
| Refrigerated | 14 days |
| Frozen | 28 days |