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Test Code Billings Clinic: 8665 Mayo: LAMO Lamotrigine, Serum

Reporting Name

Lamotrigine, S

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Monitoring serum concentration of lamotrigine

 

Assessing compliance

 

Adjusting lamotrigine dose in patients receiving other anticonvulsant drugs which interact pharmacokinetically with lamotrigine

Method Name

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Specimen Type

Serum


Specimen Required


Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. Draw blood immediately before next scheduled dose.

2. For sustained-release formulations ONLY, draw blood a minimum of 12 hours after last dose.

3. Spin down within 2 hours of draw.

4. Remove serum from serum gel tube if applicable.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 28 days
  Ambient  28 days
  Frozen  28 days

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK
 

Reference Values

Patients receiving therapeutic doses usually have lamotrigine concentrations of 2.5-15.0 mcg/mL.

Interpretation

The serum concentration should be interpreted in the context of the patient's clinical response and may provide useful information in patients showing poor response (noncompliance?) or adverse effects, particularly when lamotrigine is co-administered with other anticonvulsant drugs.

 

While most patients show response to the drug when the trough concentration is in the range of 2.5 to 15.0 mcg/mL, and show signs of toxicity when the peak serum concentration is greater than 20 mcg/mL, some patients can tolerate peak concentrations as high as 70 mcg/mL.

Day(s) and Time(s) Performed

Monday through Friday; Continuous until 2 p.m.

Saturday; Continuous until 1 p.m.

Sunday; 11 a.m.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

80175

LOINC Code Information

Test ID Test Order Name Order LOINC Value
LAMO Lamotrigine, S 6948-4

 

Result ID Test Result Name Result LOINC Value
80999 Lamotrigine, S 6948-4

Forms

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-Neurology Specialty Testing Client Test Request (T732)

-General Request (T239)

-Therapeutics Test Request (T831)