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Oct 2, 2015

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100

UWHC,UWMF,

Clinical Hub,Tools & Resources,UWHC Lab Test Directory,Toxicology

Carbamazepine

Carbamazepine (TEG) Toxicology Lab Test

Name: Carbamazepine

Test Name: Carbamazepine

Health Link Test Code: TEG

LIS Test Code: MAZE

CPT Code(s): 80156

Methodology: Enzyme Immunoassay

Clinical Information:

Anticonvulsant.

Days Performed: Daily, 24 hours.

In-Lab Turnaround Time: 4 hours.

Stat In-Lab Turnaround Time: 1 hour.

Specimen: Blood

Collection Container: Red top

Collection Instructions:

Collect specimen 15 - 30 minutes prior to morning dose.

Collection Volume: 2 mL

Pediatric Collection Volume: 0.4 mL

Stability Ambient:

2 days

Stability Refridgerated:

7 days

Stability Frozen:

1 month

Sample Analyzed: Serum

Testing Volume: 1 mL

Pediatric Testing Volume: 0.2 mL

Specimen Processing:

Centrifuge within two hours of collection. Transfer cell-free serum to plastic vial. Refrigerate.

Specimen Transport:

Transport specimen to UWHC Hospital Laboratory. Transport with coolant pack if coming from clinic location.

Unacceptable Criteria:

Specimens collected in red cap with yellow ring (SST) tubes are not acceptable.

Interpretation:

Generally effective therapeutic concentration: 4.0-12.0 ug/mL 

Critical: 15.0 ug/mL

Interpretation Type: Interpretive Guidelines

Critical Calls: yes

Additional Information:

Result of "BELOW" indicates that the result is below the method detection limit of 1.9 ug/mL. The half-life is approximately 12-36 hours. The peak level occurs in 2-6 hours. Carbamazepine is extensively hepatically metabolized. The principle metabolite, carbamazepine-10,11-epoxide, is an active metabolite whose plasma concentration may be increased in the presence of enzyme inducers or valproic acid. Carbamazepine undergoes autoinduction of metabolism (maximal effect seen in three to four weeks) which decreases the half-life and plasma concentration over time. Drug interactions do occur and blood levels and half-life tend to be decreased in the presence of other anticonvulsant drugs because of enzyme induction.