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Lamotrigine Metabolite (Mass Concentration) in Serum

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

This test measures the amount of lamotrigine’s active metabolite in your blood. It helps doctors monitor your treatment for epilepsy or bipolar disorder.

Quick summary

["This test helps ensure your medication dose is safe and effective."]

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

Key facts at a glance

LOINC
33527-3
Short code
Deprecated LA Methadone Metab Ur-mCnc
Synonyms
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Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Matters

Lamotrigine is a medication used to control seizures or stabilize mood in conditions like epilepsy or bipolar disorder. Its active metabolite works similarly to the drug itself. Regular monitoring helps prevent side effects or treatment resistance by checking how much of this metabolite is in your bloodstream.

What to Expect During the Test

A small blood sample will be taken from your arm by a healthcare professional. You may feel a slight pinch, but it usually doesn’t cause discomfort. The sample is sent to a lab for analysis.

How the Results Are Used

Your doctor will review the results to adjust your medication dose if needed. This helps balance effectiveness with minimizing side effects. Results may vary based on your health, other medications, and how your body processes the drug.

Possible Side Effects or Considerations

While rare, high levels of lamotrigine or its metabolite can cause serious side effects like rash, dizziness, or nausea. Always inform your doctor about any symptoms you experience, especially if you develop a rash while taking this medication.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Lamotrigine Metabolite Level

Frequently asked questions

Why was I asked to have this test?
Your doctor may recommend this test if you’re on lamotrigine or its metabolite to check if your dose is working well for your condition. It helps prevent side effects and ensures your medication is effective.
What does a low or high result mean?
Low levels might mean your dose isn’t providing enough benefit, while high levels could indicate potential side effects. Your doctor will discuss the results with you and adjust your treatment plan if needed.
Can I eat or drink before this test?
You can eat and drink normally unless your doctor specifies otherwise. This test only requires a blood sample, so fasting isn’t necessary.
  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