Free and Total Valproate, Serum/Plasma — Panel
Measures the amount of valproate in blood, including the portion not bound to proteins, to help guide medication dosing and monitor for adverse effects.
["This blood test helps determine how much valproate is active in your body and whether your current dose is appropriate."]
Key facts at a glance
- LOINC
- 57775-9
- Short code
- Valproate.free + Valproate pnl SerPl
- Synonyms
- Valproate.free + Valproate pnl SerPl
- Category
- liver
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 44
- Ref high
- 147
- Critical range
- — – 151 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84075
- SNOMED
- 27550007
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What is this test?
Valproate is a medicine used to treat seizures and certain mood disorders. This test measures total valproate in serum or plasma, as well as free valproate, which is the portion not bound to blood proteins and is available to the body.
Why might I need this test?
Your clinician may order this test when starting or changing valproate treatment, when symptoms suggest the medicine level is too low or too high, or when another medication may affect valproate levels.
How is the test performed?
A blood sample is collected and separated into serum or plasma in a laboratory. The laboratory measures total and free valproate using a validated laboratory method.
How do I prepare for the test?
Take valproate exactly as prescribed and tell your clinician the time of your last dose. The sample is often collected near the expected time that your clinician has established for monitoring, because drug levels can change throughout the day.
Reference range
Adult: 44-147 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
A low total or free valproate level may lead to inadequate seizure control or other signs that the dose is too low. A high level can increase the risk of side effects, including excessive sleepiness, tremor, confusion, or liver injury, although test results must be interpreted with symptoms, dosing times, and other medications. Changes in blood proteins, liver function, pregnancy, and drug interactions can also affect the relationship between total and free valproate.
Short name
Free and total valproate
Frequently asked questions
What is the difference between total and free valproate?
Does the time of my last dose affect the result?
Can other medicines change my valproate level?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy