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HelpTest Code GABA Gabapentin, Serum
Additional Codes
| Mayo Test ID |
|---|
| GABA |
Reporting Name
Gabapentin, SUseful For
Monitoring serum gabapentin concentrations
Assessing compliance
Adjusting dosage in patients
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Serum RedSpecimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Red top (serum gel/SST is not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Collect specimen immediately before next scheduled dose.
2. Within 2 hours of collection, centrifuge and aliquot serum into plastic vial.
Specimen Minimum Volume
0.2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum Red | Refrigerated (preferred) | 28 days | |
| Ambient | 28 days | ||
| Frozen | 28 days |
Reference Values
2.0-20.0 mcg/mL
Toxic Range: ≥25.0 mcg/mL
Day(s) Performed
Monday through Saturday
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
80171
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| GABA | Gabapentin, S | 9738-6 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 80826 | Gabapentin, S | 9738-6 |
Interpretation
Therapeutic ranges are based on specimens collected immediately before the next dose (ie, trough).
Most epileptic patients show a response to the drug when the trough concentration is in the range of 2 to 20 mcg/mL. Therapeutic drug monitoring may be useful due to inter-individual variation in pharmacokinetics and dose-dependent bioavailability; specimens for measurements should be collected before the morning dose since the short half-life may affect the interpretation of the concentration.
Clinical Reference
1. Hiemke C, Bergemann N, Clement HW, et al. Consensus guidelines for therapeutic drug monitoring in neuropsychopharmacology: Update 2017. Pharmacopsychiatry. 2018;51(1-02):9-62
2. Patsalos PN, Berry DJ, Bourgeois BF, et al. Antiepileptic drugs-best practice guidelines for therapeutic drug monitoring: a position paper by the subcommission on therapeutic drug monitoring, ILAE Commission on Therapeutic Strategies. Epilepsia. 2008;49(7):1239-1276
3. Johannessen SI, Tomson T. Pharmacokinetic variability of newer antiepileptic drugs: when is monitoring needed? Clin Pharmacokinetics. 2006;45(11):1061-1075
4. Milone MC, Shaw LM: Therapeutic drugs and their management. In: Rifai N, Chiu RWK, Young I, Burnham CAD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier; 2023:420-453
Report Available
Same day/1 to 2 daysMethod 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)
-Therapeutics Test Request (T831)