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Test Code LAB470 Gabapentin, Serum

Additional Codes

GABA

Useful For

Monitoring serum gabapentin concentrations

 

Assessing compliance

 

Adjusting dosage in patients

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum Red


Specimen 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

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.

Method Description

Gabapentin and the internal standard are separated from other serum constitutes with analysis on a tandem mass spectrometer equipped with an electrospray ion source using multiple reaction monitoring.(Unpublished Mayo method)

Report Available

Same day/1 to 2 days

Specimen Retention Time

2 weeks

Reject 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)

-Therapeutics Test Request (T831)

Secondary ID

80826