Carbamazepine in Serum (Quantitative)
This test measures the amount of carbamazepine, a medication used to treat certain types of seizures or nerve pain, in your blood. It helps doctors monitor your drug levels to ensure they’re effective and safe.
["This test helps your healthcare provider check if your carbamazepine dose is working properly and at safe levels."]
Key facts at a glance
- LOINC
- 41473-0
- Short code
- CARBEPOX
- Synonyms
- Carbamazepine EP DBS-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Dried blood spot (DBS) collection card - Whatman 903 Protein Saver or equivalent FDA-approved filter paper card, with desiccant packets
- Units
- N/A
- Ref low
- 0.5
- Ref high
- 4
- Critical range
- — – 9 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–99 years
- Method
- Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
- CPT
- 80299
- SNOMED
- 395156006
- Specimen volume
- 50-75 microliters whole blood per spot (minimum 3 spots filled completely)
- Stability
- DBS samples are stable for 14 days at room temperature (15-25°C), 30 days at 2-8°C, and 90 days at -20°C or below. Protect from light and humidity. Allow cards to dry completely (minimum 3 hours) before packaging.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
Why This Test Is Done
Your doctor may order this test if you’re taking carbamazepine to manage conditions like epilepsy, bipolar disorder, or trigeminal neuralgia. Regular monitoring helps prevent side effects, such as dizziness, drowsiness, or blood abnormalities, while ensuring the drug remains effective.
How the Test Works
A blood sample is taken from a vein in your arm. The sample is then analyzed using a specialized lab technique to measure the precise concentration of carbamazepine in your serum. This helps your doctor adjust your dose if needed.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if instructed by your doctor. Wear comfortable clothing and bring any medications you’re currently taking.
What to Expect During the Test
The test involves a quick needle stick to draw blood. You may feel a slight pinch, but it usually takes only a few seconds. The blood is then sent to a lab for analysis, and results are typically available within 1–3 business days.
Reference range
Therapeutic range for carbamazepine 10,11-epoxide metabolite is not well established; however, levels are typically interpreted alongside parent carbamazepine concentrations. Epoxide/parent ratio is normally 0.1-0.3. Generally, epoxide levels of 0.5-4.0 mcg/mL are considered acceptable when parent drug is within therapeutic range (4-12 mcg/mL).N/A
No fasting required. Specimen should be collected as a trough level, immediately prior to the next scheduled dose, to ensure consistent therapeutic drug monitoring. Patients should be on a stable dose for at least 3-5 days before sampling. Document time of last dose on requisition.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Carbamazepine levels are monitored to balance effectiveness and safety. Too little may mean seizures or pain aren’t controlled, while too much can cause toxicity, affecting organs like the liver or kidneys. Your doctor will use these results to optimize your dose and avoid these risks.
Short name
Carbamazepine Level
Frequently asked questions
How long does it take to get my results?
What does a low or high carbamazepine level mean?
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 16, 2026. · Read our editorial policy