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HelpTest Code LAB475 Lamotrigine, Serum
Additional Codes
LAMO
Useful For
Monitoring serum concentration of lamotrigine
Assessing compliance
Adjusting lamotrigine dose in patients receiving other anticonvulsant drugs that interact pharmacokinetically with lamotrigine
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumSpecimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Collect blood immediately before next scheduled dose.
2. For sustained-release formulations only, collect blood a minimum of 12 hours after last dose.
3. Centrifuge within 2 hours of collection
4. For red-top tubes, immediately aliquot serum into a plastic vial.
5. For serum gel tubes, aliquot serum into a plastic vial within 24 hours of collection.
On-campus collections: Tube to 99 or deliver to University Extension Hospital Room EH318. Submission Container/Tube: Plastic vial, Refrigerated.
Off-campus collections: Centrifuge and aliquot within 2 hours. Specimen to be stored/transported Refrigerated.
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 |
Reference Values
Patients receiving therapeutic doses usually have lamotrigine concentrations of 3.0-15.0 mcg/mL.
Day(s) Performed
Monday through Sunday
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 |
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 coadministered with other anticonvulsant drugs.
While most patients show response to the drug when the trough concentration is in the range of 3.0 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.
Method Description
Samples are diluted and extracted online by high turbulence liquid chromatography with detection by tandem mass spectrometry.(Unpublished Mayo method)
Report Available
Same day/1 to 2 daysSpecimen Retention Time
14 daysReject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Method Name
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
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)