Test Code

Quest Code

CPT Codes

Preferred Specimen
1 mL serum collected in a red-top tube (no gel)

Patient Preparation
Draw sample 2 hours after last dose

Minimum Volume
0.5 mL

Other Acceptable Specimens
Plasma collected in: EDTA (lavender-top) tube, sodium heparin (green-top) tube or lithium heparin (green-top) tube

Do not use gel barrier/Serum Separator tubes. Separate serum or plasma from red cells as soon as possible; pipette or pour into plastic transport tubes.

Transport Temperature

Specimen Stability
Room temperature: 5 days
Refrigerated: 12 days
Frozen: 30 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Gel barrier/Serum Separator Tube (SST®)

Chromatography/Mass Spectrometry

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule
Set up: Tues-Sat; Report available: 2-4 days

Reference Range
2.7-4.1: (peak) following a single dose of 900-1800 mg/day.
4.0-8.5: (peak) following a multiple dose of 900-1800 mg/day administration.

The reference range is evolving. Seizure control has been observed at levels in excess of 4 mcg/mL.

Clinical Significance
Gabapentin is an anticonvulsant drug commonly used as adjunctive therapy to treat partial seizures. Therapeutic drug monitoring is useful to optimize dose and to avoid toxicity.

Performing Laboratory
Quest Diagnostics Valencia Nichols Institute
27027 Tourney Road
Valencia, CA 91355-5386

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.