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Lamotrigine concentration (serum/plasma)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of lamotrigine, a medication used to treat epilepsy and certain mood disorders, in your blood. It helps your healthcare provider monitor your dose and ensure it’s working safely.

Quick summary

["Your lamotrigine levels help balance your treatment for seizures or mood stability."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
98414-6
Short code
lamoTRIgine Ur Ql Cfm
Synonyms
lamoTRIgine Ur Ql Cfm
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
confirm
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Is Done

Doctors order lamotrigine blood tests to check if your medication is at the right level to control seizures or mood symptoms without causing side effects. It’s especially important if you’re starting, stopping, or adjusting your dose.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm or vein for a blood draw. If you’re on other medications, let your doctor know, as they may affect how lamotrigine works in your body.

What the Results Mean

Results show your current lamotrigine concentration. Low levels may mean your dose isn’t strong enough, while very high levels could signal risk of side effects like rash or dizziness. Your doctor will interpret these results with your symptoms and medical history.

Common Side Effects to Watch For

While rare, high lamotrigine levels can cause side effects like skin rashes, nausea, or dizziness. If you experience severe rash (like Stevens-Johnson syndrome), stop taking lamotrigine and seek medical help immediately.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Lamotrigine levels are critical for epilepsy and bipolar disorder management. Optimal dosing prevents seizures or mood episodes while minimizing risks. Regular monitoring helps avoid toxicity or inadequate control of symptoms.

Short name

Lamotrigine Level

Frequently asked questions

How often should I get this test?
Your doctor will determine your testing schedule based on your treatment plan. Typically, it’s done when you start lamotrigine, after dose changes, or if you experience new symptoms.
What happens if my levels are too low?
If levels are too low, your doctor may increase your dose to improve seizure or mood control. They’ll adjust slowly to avoid side effects.
Can food or other medications affect this test?
Some medications (like valproate) can change lamotrigine levels. Always tell your doctor about all medications, supplements, or health conditions before testing.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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