Lamotrigine, Serum
Use
The test is used for monitoring serum concentration of lamotrigine, assessing compliance, and adjusting lamotrigine dose in patients receiving other anticonvulsant drugs that interact pharmacokinetically with lamotrigine. Lamotrigine is approved for therapy of bipolar I disorder and a range of seizure disorders. The therapeutic range is relatively wide, between 3 to 15 mcg/mL for most individuals. The drug's bioavailability is high and its metabolism involves glucuronic acid conjugation to inactive metabolites.
Special Instructions
If not ordering electronically, complete and send one of the designated forms: Neurology Specialty Testing Client Test Request, General Request, or Therapeutics Test Request. Proper specimen collection timing is crucial, particularly for sustained-release formulations.
Limitations
The method may show variability if inappropriate specimen collection or handling occurs, particularly in the use of serum separator tubes where serum must be removed from gel within 24 hours of collection. Therapeutic levels may be affected by the concurrent use of drugs such as phenytoin or carbamazepine, and valproic acid therapy can lengthen the half-life.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 6948-4
- 6948-4
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL
Container
Plastic vial
Collection Instructions
1. Collect blood immediately before next dose. 2. Only for sustained-release formulations, collect blood a minimum of 12 hours post-dose. 3. Centrifuge within 2 hours. 4. Aliquot serum into a plastic vial immediately for red-top, or within 24 hours for serum gel tubes.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 28 days |
| Refrigerated | 28 days |
| Frozen | 28 days |