Test ID CARTA Carbamazepine, Total, Serum
Useful For
Monitoring therapy
Determining compliance
Assessing toxicity
Method Name
Immunoassay
Reporting Name
Carbamazepine, Tot, SSpecimen Type
Serum RedContainer/Tube: Red top
Specimen Volume: 0.5 mL
Collection Instructions: Red-top tubes should be centrifuged and aliquoted within 2 hours of collection.
Forms: If not ordering electronically, complete, print, and send a Neurology Test Request Form-General (T732) with the specimen (http://www.mayomedicallaboratories.com/it-mmfiles/neurology-request-form.pdf)
Specimen Minimum Volume
Rochester: 0.25 mL, Jacksonville: 0.20 mL
Specimen Stability Information
Specimen Type | Temperature | Time |
---|---|---|
Serum Red | Refrigerated (preferred) | 14 days |
Frozen | 28 days | |
Ambient | 14 days |
Clinical Information
Carbamazepine (Tegretol) is used in the control of partial seizures with both temporal lobe and psychomotor symptoms, and 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 75%.
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 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 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. Optimal response occurs when the CBZ10-11 level is in the range of 0.4 to 4.0 mcg/mL.
Day(s) Performed
Monday through Sunday; Continuously
Report Available
Same day/1 dayPerforming Laboratory

Test Classification
This test has been cleared or approved by the U.S. 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