Lab Dept:


Test Name:


General Information

Lab Order Codes:




CPT Codes:

80339 - Antiepileptics, not otherwise specified; 1-3
G0480 – Drug, test, definitive

Test Includes:

Felbamate concentration measured in ug/mL.


Test Indications:

Determining whether a poor therapeutic response is attributable to noncompliance or lack of drug effectiveness. Monitoring changes in serum concentrations resulting from interactions with co-administered drugs such as barbiturates and phenytoin.

Lab Testing Sections:

Chemistry - Sendouts

Referred to:

MedTox Laboratories (MedTox Test: 165)

Phone Numbers:

MIN Lab: 612-813-6280

STP Lab: 651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

2 days, test performed daily

Special Instructions:

If this is a STAT order, please check with the provider to see if the specimen should be shipped immediately and performed STAT by the reference lab at an additional cost. If immediate shipment is necessary, please call the lab to make arrangements.

Obtain specimen 1 hour prior to next dose.


Specimen Type:



Red top tube
Alternate: Green (Lithium Heparin) tube

Draw Volume:

6 mL (Minimum: 0.6 mL) blood

Processed Volume:

2 mL (Minimum: 0.2 mL) serum/plasma

Note: Submission of the minimum volume does not allow for repeat analysis and may result in a QNS (quantity not sufficient) test result.


Routine venipuncture


Special Processing:

Lab Staff: Centrifuge specimen, remove serum aliquot into a screw-capped round bottom plastic vial. Store and ship at refrigerated temperatures. Forward promptly.

Patient Preparation:


Sample Rejection:

Mislabeled or unlabeled specimens


Reference Range:

40 - 100 ug/mL

Note: Stated range of 40 - 100 ug/mL is the observed range of concentrations in patients successfully treated with felbamate without apparent ill effect. The therapeutic range is not established.

Critical Values:

Toxic serum concentrations for felbamate have not been established.


Report Limit: 2 ug/mL


MedTox: Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS)


MedTox Laboratories (October 2014)


6/11/2004: Test moved from MedTox Laboratories to Mayo Medical Laboratories. Note change in reference range from 40 –100 ug/mL to 25 – 100 ug/mL. Change in method from GC-FID to HPLC.
5/6/2010: MedTox CPT update.
7/12/2010: Units update from ug/mL to mcg/mL.
9/27/2010: Method change at Mayo, previously listed as HPLC.
12/6/2010: Information updated for MedTox, Mayo information no longer referenced. All specimens to be sent to MedTox.
1/7/2015: CPT update
2/1/2016: CPT update