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Valproic Acid
Test CodeVALP
Alias/See Also
Depakote
Depakene
Valproic Acid Total
Divalproex
Depakene
Valproic Acid Total
Divalproex
CPT Codes
80164
Preferred Specimen
1.0 mL serum collected in a Red top (No Gel) tube
Minimum Volume
0.1 mL
Other Acceptable Specimens
Plasma- Lithium Heparin (PST)
Plasma- Sodium Heparin
Plasma- EDTA (Lavender)
Serum- Red Top
Serum- SST or Tiger Top
Plasma- Sodium Heparin
Plasma- EDTA (Lavender)
Serum- Red Top
Serum- SST or Tiger Top
Instructions
Specimens for valproic acid analysis should be drawn just prior to dose, preferably in the fasting state. More frequent monitoring may be necessary when administering valproic acid in the presence or during the withdrawal of other anti-epileptic agents.
Transport Temperature
Room temperature
Specimen Stability
Room Temperature: 2 days at 20-25°C
Refrigerated: 7 days at 2-8°C.
Frozen: 3 months at -20 °C. Freeze only once.
Refrigerated: 7 days at 2-8°C.
Frozen: 3 months at -20 °C. Freeze only once.
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Samples not labeled with complete first and last name of patient and date of birth.
Grossly hemolyzed specimen.
Grossly hemolyzed specimen.
Methodology
Immunoassay
Setup Schedule
Sun - Sat
Report Available
Same day
Reference Range
50 - 100 µg/mL
Clinical Significance
Valproic acid (VPA; 2-propylpentanoic acid; Depakene) is a relatively new anticonvulsant medication which is used chiefly for the treatment of primary and secondary generalized seizures, but is also effective against absence seizures It is particularly effective in myoclonus, and is the drug of choice in photosensitive epilepsy. At therapeutic concentrations, over 90 % of VPA in the circulation is bound to plasma proteins, primarily albumin. Binding is saturable, and at high VPA concentrations, the free fraction increases. Other compounds can compete for VPA binding to albumin; these include salicylic acid and free fatty acids. The concentration of VPA in cerebrospinal fluid is correlated to both the total and unbound concentrations of the drug in plasma.
VPA is converted to a complex mixture of metabolites via β and ω-oxidation and conjugation. Some metabolites show significant anti-convulsant activity, while others may be responsible for some of the drug’s toxic side effects. VPA has the fewest adverse effects of all the widely-used anti-epileptic agents. The most common side effects are gastrointestinal disturbances such as nausea and vomiting. Some incidences of tremor, coma or stupor have been noted; these often occur in conjunction with co-administration of other anti-epileptic drugs. Rare occurrences of hepatic failure, Reye-like syndrome, pancreatitis or thrombocytopenia are thought to be individualized reactions unrelated to drug levels
VPA is converted to a complex mixture of metabolites via β and ω-oxidation and conjugation. Some metabolites show significant anti-convulsant activity, while others may be responsible for some of the drug’s toxic side effects. VPA has the fewest adverse effects of all the widely-used anti-epileptic agents. The most common side effects are gastrointestinal disturbances such as nausea and vomiting. Some incidences of tremor, coma or stupor have been noted; these often occur in conjunction with co-administration of other anti-epileptic drugs. Rare occurrences of hepatic failure, Reye-like syndrome, pancreatitis or thrombocytopenia are thought to be individualized reactions unrelated to drug levels
Performing Laboratory
Frederick Health Laboratory 400 W 7th Street Frederick, MD 20701
Last Updated: August 26, 2021
