Valproic Acid (Valproate), Peak Level, Serum/Plasma — Mass Concentration
A blood test that measures the highest valproate level after a dose to help guide dosing and check for possible toxicity.
["This test shows how much valproate is in your blood at its peak and can help your clinician balance effectiveness and safety."]
Key facts at a glance
- LOINC
- 73677-7
- Short code
- Valproate Peak SerPl-mCnc
- Synonyms
- Valproate Peak SerPl-mCnc
- 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?
This test measures the concentration of valproate, also called valproic acid, in your blood or plasma. A peak sample is collected when the medication level is expected to be at its highest after a dose.
Why might I need this test?
Your clinician may order this test to check whether a valproate dose is likely to be effective, especially when seizures or mood symptoms are not well controlled. It may also be used when side effects suggest that the dose is too high.
How is the test performed?
A blood sample is drawn from a vein and analyzed in a laboratory. Because valproate levels rise and fall throughout the day, the timing of the sample after your last dose is important and should follow your clinician's instructions.
How do I prepare for the test?
Take valproate exactly as prescribed and note the time of your last dose. Do not skip or change a dose unless your clinician tells you to, because this can affect both the test result and your seizure control.
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 peak level that is lower than expected may suggest inadequate dosing, poor absorption, or reduced medication adherence. A level that is higher than expected may increase the risk of dose-related side effects, such as unusual sleepiness, tremor, confusion, or liver injury. Results must be interpreted with your dose, timing, symptoms, kidney function, liver function, and other medications.
Short name
Valproate Peak Level
Frequently asked questions
What is a valproate peak level?
When should the blood sample be taken?
Does an abnormal result mean I should stop taking valproate?
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