What is the Lamotrigine test?

The Lamotrigine blood test measures the concentration of lamotrigine, an anticonvulsant and mood-stabilising medication, in the bloodstream. Lamotrigine is commonly prescribed for epilepsy and bipolar disorder, and occasionally for other neurological or psychiatric conditions.

Although lamotrigine has a wider therapeutic range than some other medications, blood level monitoring can be helpful in ensuring the dose is effective, safe, and consistent, particularly when symptoms are not well controlled or side effects occur.

This test is part of therapeutic drug monitoring (TDM) and helps personalise treatment based on how an individual metabolises the medication.

Why do I need a Lamotrigine test?

Lamotrigine levels can vary between individuals due to metabolism, interactions with other medications, or adherence issues. Monitoring helps optimise treatment and reduce risk.

You may need a Lamotrigine test if you:

• Are being treated for epilepsy
• Are taking lamotrigine for bipolar disorder
• Have ongoing seizures or mood instability
• Have recently changed dose
• Are starting or stopping interacting medications
• Experience side effects
• Need to check medication adherence

Symptoms linked to abnormal lamotrigine levels may include:

• Persistent seizures
• Mood instability
• Dizziness
• Headache
• Nausea
• Blurred vision
• Coordination problems

Benefits of the Lamotrigine test

• Supports optimal dosing
  Helps ensure therapeutic effectiveness.
• Reduces side-effect risk
  Identifies excessive drug levels.
• Useful in treatment-resistant cases
  Clarifies whether dose is adequate.
• Supports epilepsy management
  Helps maintain seizure control.
• Useful in bipolar disorder treatment
  Supports mood stabilisation.
• Clinically recognised monitoring test
  Used in neurology and psychiatry.
• Helps assess drug interactions
  Important when medications change.
• Simple blood test
  Requires only one sample.

Step by step – how the test works

You can access Lamotrigine testing UK-wide through two options:

1. Clinic appointment
   Attend your nearest UK clinic, where a healthcare professional will take your blood sample.
2. At-home or hotel visit (£60 extra)
   A qualified phlebotomist comes to your home or hotel, maintaining correct sample timing.

Your sample is analysed in an accredited UK laboratory, and results are delivered securely.

Your results explained

Low lamotrigine level

May indicate under-dosing, poor absorption or non-adherence.

Typical UK interpretation:

• < 3 mg/L

Therapeutic lamotrigine level

Suggests effective and safe medication concentration.

Typical UK interpretation:

• 3–14 mg/L

High lamotrigine level

May increase risk of side effects or toxicity.

Typical UK interpretation:

• > 14 mg/L

Therapeutic ranges may vary slightly depending on clinical context.