Carbamazepine-10, 11 Epoxide and Total Carbamazepine (Sendout)

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General Information

Lab Name
Carbamazepine_10,11 Epox + Tot
Lab Code
RCBAMZ
Epic Name
Carbamazepine_10,11 Epox & Tot
External Test Id
CARBG
Description

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.

Ordering Note: If both Carbamazepine and metabolite Carbamazepine-10,11-Epoxide are requested, order Carbamazepine (Tegretol) [CBAM] along with this test.

Collection Timing: Draw blood 12 hours (trough) after last dose.

Synonyms
11 Epoxide, 11), Carbamazepine Epoxide, Carbatrol, CARBG, Epoxide (10, Tegretol 10, Tegretol Metabolite
Components
Code Name
RCBAMT Carbamazepine, Total
RCBAMX Carbamazepine_10,11_Epoxide

Interpretation

Method

Carbamazepine, Total: Homogenous Microparticle Agglutination Immunoassay
Carbamazepine-10,11-Epoxide: High-Performance Liquid Chromatography (HPLC)

Reference Range
See individual components
Ref. Range Notes

Interpretation:

The clinically acceptable serum concentration of carbamazepine-10,11-epoxide (CBZ10-11) is not well established, but 4.0 mcg/mL has often been used as an upper limit for its therapeutic range.

The ratio of CBZ10-11 to carbamazepine is usually < or =0.2 mcg/mL in symptomatic adults and < or =0.3 mcg/mL in children.

Clinical correlation is aided by comparing values obtained when the patient is symptomatic with those obtained when the patient has improved.

Interferences and Limitations

Cautions: Routine determination of carbamazepine-10,11-epoxide (CBZ10-11) is not clinically indicated. It should be considered when the source of treatment in associated symptoms is not obvious.

Ordering & Collection

Specimen Type
Blood
Collection

6 mL blood in RED TOP tube

Unacceptable: Any other tube type, including gel tubes.

Handling Instructions

Outside Laboratories: Centrifuge sample and transfer serum to a separate plastic vial. Refrigerate serum.

Stability: Refrigerated (preferred): 7 days; Frozen: 28 days; Ambient: 48 hours.

Reject Due To: Gross hemolysis, gross lipemia, gross icterus.

Quantity
Requested: 2 mL serum
Minimum: 1 mL serum

Processing

Receiving Instructions

Centrifuge sample and transfer serum to a separate plastic vial. Refrigerate serum.

Sendouts:

  • Order Mayo Test: CARBG.
  • Interfaced: Yes.

Stability: Refrigerated (preferred): 7 days; Frozen: 28 days; Ambient: 48 hours.

Reject Due To: Gross hemolysis, gross lipemia, gross icterus.

Misc Sendout

Performance

Lab Department
Sendouts Mayo Lab (RF)(MARF)
Frequency
Performed: Tuesday. Report Available: 1-7 days.
Available STAT?
No
Performing Location(s)
Sendout Mayo Clinic Laboratories
800-533-1710

200 First Street Southwest
Rochester, MN 55901

Billing & Coding

CPT Codes
80156, 80161
LOINC
3432-2