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HelpTest ID CARBG Carbamazepine-10,11-Epoxide, Serum
Useful For
Monitoring patients exhibiting symptoms of carbamazepine toxicity whose total serum carbamazepine concentration is within the therapeutic range, but who may be producing significant levels of the active metabolite epoxide, which can accumulate to concentrations equivalent to carbamazepine
Specimen Type
Serum RedSpecimen Required
Collection Container/Tube: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 2 mL
Collection Instructions:
1. Draw blood 12 hours (trough value) after last dose.
2. Centrifuge and aliquot serum into a plastic vial.
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum Red | Refrigerated (preferred) | 7 days |
| Frozen | 28 days | |
| Ambient | 48 hours |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Reference Values
CARBAMAZEPINE, TOTAL
Therapeutic: 4.0-12.0 mcg/mL
Critical value: ≥15.0 mcg/mL
CARBAMAZEPINE-10,11-EPOXIDE
Therapeutic concentration: 0.4-4.0 mcg/mL
Toxic concentration: ≥8.0 mcg/mL
Day(s) Performed
CARTA: Monday through Sunday
1011E: Tuesday
Report Available
Same day/1 to 7 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
80156-Carbamazepine, Tot, S
80161-Carbamazepine-10,11-Epoxide
Forms
If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.