Carbamazepine concentration (serum/plasma)
This test measures the amount of carbamazepine, a medication used to treat certain types of seizures or nerve pain, in your blood.
["Your blood carbamazepine level helps doctors check if the drug is working properly and at safe levels."]
Key facts at a glance
- LOINC
- 9415-1
- Short code
- CBZEPOX
- Synonyms
- Carbamazepine EP SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top serum tube or serum separator tube (SST); plasma may be collected in heparin or EDTA tubes
- Units
- N/A
- Ref low
- 10
- Ref high
- 50
- Critical range
- — – 15 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) or High-Performance Liquid Chromatography (HPLC)
- CPT
- 80299
- SNOMED
- 395087007
- Specimen volume
- 1-2 mL of serum or plasma
- Stability
- Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 100
- Lipemia max
- 200
- Icterus max
- 40
- TAT
- 24–72 hours
- Order
- routine
Why This Test Is Done
Your healthcare provider may order this test if you’re taking carbamazepine to manage conditions like epilepsy, bipolar disorder, or trigeminal neuralgia. It helps monitor whether your dose is appropriate and if your body is processing the medication safely.
What to Expect Before the Test
No special preparation is needed. You may have a small needle inserted into your arm or vein to draw blood. If you’re on blood thinners, let your provider know before the test.
What the Results Mean
Results are used to adjust your carbamazepine dose if needed. Too little may mean the medication isn’t working, while too much could increase side effects like dizziness or drowsiness.
Common Side Effects to Watch For
While carbamazepine is generally safe, high levels can cause dizziness, nausea, or fatigue. Always report any unusual symptoms to your doctor.
Reference range
Therapeutic range for carbamazepine 10,11-epoxide is not well established but typically considered significant when combined parent drug and metabolite exceed therapeutic threshold; active metabolite expected to be present at 10-50% of parent carbamazepine concentrationN/A
No fasting required. Trough levels should be drawn just before the next dose, typically in the morning. Patient should be on a stable dose for at least 5-7 days before sampling for accurate steady-state levels.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Carbamazepine levels are critical because it can interact with other medications, affect liver function, and sometimes cause serious side effects like rash or blood disorders. Regular monitoring helps prevent complications and optimize treatment.
Short name
Carbamazepine Level
Frequently asked questions
Why might my doctor want to check my carbamazepine level?
What happens if my carbamazepine level is too high or too low?
Can I eat or drink before this test?
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