Carbamazepine concentration in serum/plasma
This test measures the amount of carbamazepine, a medication used to control certain types of seizures or manage nerve pain, in your blood.
["Helps monitor your dose to stay within safe levels."]
Key facts at a glance
- LOINC
- 3432-2
- Short code
- CARB
- Synonyms
- carBAMazepine SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top serum tube (no anticoagulant) or serum separator tube (SST)
- Units
- N/A
- Ref low
- 4
- Ref high
- 12
- Critical range
- — – 20 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Immunoassay (e.g., PETINIA, EMIT, FPIA) or Chromatography (HPLC, LC-MS/MS)
- CPT
- 80156
- SNOMED
- 395078004
- Specimen volume
- 1.0-2.0 mL serum
- Stability
- Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C): 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 100
- Lipemia max
- 500
- Icterus max
- 25
- TAT
- 2–24 hours
- Order
- routine
Why This Test Is Done
Your healthcare provider may order this test if you’re taking carbamazepine to ensure it’s working properly and to avoid side effects like dizziness, drowsiness, or balance problems. It’s also used to check if your dose needs adjustment, especially if you’re taking other medications that interact with carbamazepine.
What to Expect Before the Test
No special preparation is needed. You’ll have a small needle inserted into your arm or vein to draw blood. It usually takes a few minutes, and you may feel a brief pinch. If you’re on blood thinners, let your provider know before the test.
What the Results Mean
Results help determine if your carbamazepine levels are too high (which can cause toxicity) or too low (which may mean your seizures aren’t controlled). Your provider will discuss these results with you in the context of your overall health and treatment plan.
Common Side Effects to Watch For
While carbamazepine is generally safe, high levels can cause nausea, dizziness, or confusion. If you experience severe symptoms like rash, trouble breathing, or irregular heartbeat, seek medical attention immediately.
Reference range
Therapeutic range: 4.0-12.0 mcg/mL (trough level); Toxic: >15.0 mcg/mLN/A
No fasting required. Specimen should be collected as a trough level, immediately before the next scheduled dose, typically in the morning. Patient should be at steady-state medication (usually 2-5 days after initiating therapy or dose change).
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Carbamazepine Level
Frequently asked questions
How often should I get this test?
Can I drink alcohol before this test?
What if my results are outside the normal range?
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 15, 2026. · Read our editorial policy