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HelpTest ID CARTA Carbamazepine, Total, Serum
Ordering Guidance
This test measures carbamazepine only. For assessment of its active metabolite, carbamazepine-10,11-epoxide, which is the predominant form in children, order CARBG / Carbamazepine-10,11-Epoxide, Serum)
Specimen Required
Collection Container/Tube: Red top
Specimen Volume: 0.5 mL
Submission Container/Tube: Plastic vial
Collection Instructions: Centrifuge and aliquot serum into a plastic vial within 2 hours of collection.
Forms
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-Neurology Specialty Testing Client Test Request (T732)
-Therapeutics Test Request (T831)
Useful For
Monitoring therapy
Determining compliance
Assessing toxicity
Method Name
Homogeneous Microparticle Agglutination Immunoassay
Reporting Name
Carbamazepine, Tot, SSpecimen Type
Serum RedSpecimen Minimum Volume
0.25 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum Red | Refrigerated (preferred) | 7 days |
| Frozen | 28 days | |
| Ambient | 48 hours |
Clinical Information
Carbamazepine (Tegretol) is used in the control of partial seizures with both temporal lobe and psychomotor symptoms as well as for generalized tonic-clonic seizures. It is also used for analgesia in trigeminal neuralgia.
Carbamazepine exhibits a volume of distribution of 1.4 L/kg with an elimination half-life of 15 hours. Protein binding averages 70%.
Carbamazepine-10,11-epoxide (CBZ10-11) is an active metabolite that represents the predominant form of the drug in children. The volume of distribution of CBZ10-11 is 1.1 L/kg, and the half-life is 5 to 8 hours.
Aplastic anemia and agranulocytosis are rare side effects of treatment with carbamazepine; baseline hematologic data should be documented before treatment is initiated.
Toxicity associated with carbamazepine overdose occurs when the blood level is 15.0 mcg/mL or higher and is typified by irregular breathing, muscle irritability, and hyperreflexia; followed by hyporeflexia, tachycardia, hypotension, and impaired consciousness with coma in severe toxicity. The higher the blood level, the more severe the symptoms.
Reference Values
Therapeutic: 4.0-12.0 mcg/mL
Critical value: ≥15.0 mcg/mL
Cautions
Carbamazepine-10,11-epoxide (CBZ10-11) is not reported. A separate orderable test for this active metabolite is available (CARBG / Carbamazepine-10,11-Epoxide, Serum). Optimal response occurs when the CBZ10-11 serum level is in the range of 0.4 to 4.0 mcg/mL.
Day(s) Performed
Monday through Sunday
Report Available
Same day/1 dayPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
80156