Valproic Acid, Serum or Plasma
Also known as: Depacon®, Depakene®, Depakote®, Stavzor™, Valproate
Use
Valproate (valproic acid; divalproex sodium, a compound containing sodium valproate and valproic acid) controls absence, myoclonic, and tonic-clonic seizures in generalized, idiopathic, and symptomatic epilepsy. It is most useful in typical absence seizures. Valproate is as effective as ethosuximide in patients with absence seizures alone and is variably effective in atypical absence seizures. Although some clinicians prefer valproate for absence seizures, the American Academy of Pediatrics (Committee on Drugs, 1982) recommended that it be reserved for use when therapeutic failure or intolerance to ethosuximide occurs, because valproate causes rare but potentially fatal hepatotoxicity. Many neurologists consider valproate the drug of choice for patients with both absence and other generalized seizure types, including tonic-clonic convulsions. Its efficacy is about the same as in patients with the latter type alone.
Special Instructions
Not provided.
Limitations
Routine liver enzyme monitoring cannot prevent hepatotoxicity, which occurs idiosyncratically in very young children, usually those on multiple anticonvulsants. Valproate-induced cytopenias may be dose-related. Monitoring for hyperammonemia without liver function test abnormalities is necessary, as encephalopathy can occur. The antiepileptic activity duration does not directly correlate with plasma concentrations, and several metabolites are involved, with potential contributions to both therapeutic and adverse effects.
Methodology
Immunoassay (IA)
Biomarkers
Valproic Acid
Analyte
LOINC Codes
- 4086-5 - Valproate SerPl-mCnc
- 4086-5 - Valproate SerPl-mCnc
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL
Minimum Volume
0.3 mL
Container
Red-top tube or green-top (heparin) tube. Do not use a gel-barrier tube.
Collection Instructions
Transfer separated serum or plasma to a plastic transport tube. Peak: one to four hours after dose; trough: immediately prior to next dose.
Storage Instructions
Room temperature; stable for 14 days. Refrigerated; stable for 14 days. Frozen; stable for 14 days. Stable x3 freeze/thaw cycles.
Causes for Rejection
Gel-barrier tube; hemolysis; lipemia
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |
Other tests from different labs that may be relevant
