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Test Code CARBA Carbamazepine

Additional Codes

Epic: LAB21

Specimen Required

Specimen Type: Serum

Collection Container/Type: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 3mL

Collection Instructions: 

  1. In a patient on regular medication regimen, the sample should be drawn immediately prior to next carbamazepine dose.

  2. Centrifuge and separate cells after clot formation and within 4 hours of collection. 

Specimen Minimum Volume

0.3 mL

Specimen Stability

Room temperature: 24 hours

Refrigerated: 7 days

Frozen: 14 days

Clinical Significance

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 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 5-8 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 Range

4.00 - 12.00 µg/mL

Rejection Due To

Unlabeled, mislabeled, wrong tube type, hemolyzed, QNS, exceeds specimen stability requirements.

Day(s) and Time(s) Performed

Daily

Report Available

Same day

Method Name

Chemiluminescent microparticle immunoassay (CMIA)

LOINC

3432-2

Limitations

For diagnostic purposes, results should be used in conjunction with other data: symptoms, results of other tests, clinical impressions, etc.
Potentially interfering substances include : Hemoglobin  >500 mg/dL; Bilirubin >20 mg/dL; Triglycerides  >3000 mg/dL; Total Protein >12 g/dL 
Patients receiving mouse monoclonal antibodies for diagnosis or treatment may develop Human anti-mouse antibodies (HAMA).  HAMA may cause falsely elevated or decreased values when tested with assay kits which employ mouse monoclonal antibodies. Additional information may be required for diagnosis.
Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro immunoassays.

Aliases

Tegretol