Carbamazepine
Label Mnemonic: CBZ
Epic Lab Code: LAB22
Downtime Form: A-1a Therapeutic Drug Assay Requisition
Chemistry
6240 RCP
356-3527
Specimen(s):
Plasma
Collection Medium:
Plasma Separator Tube 4.5 mL
Alternate Collection Media:
Call laboratory for additional acceptable specimen collection containers.
Minimum:
3 mL whole blood from light green top tube or 1 Microtainer®
Testing Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around Time:
1 hour (upon receipt in laboratory)
Reference Range:
4-12 μg/mL

Critical value: >12 μg/mL
Comments:
The therapeutic range for carbamazepine is derived from the relationships between plasma level, seizure control and emergence of side effects. The approximate therapeutic range is between 4 and 12 μg/mL. However, some patients may respond effectively to levels outside these ranges. The ranges are therefore, provided only as a guide for interpretation along with other clinical symptoms, and are not to be taken as the sole indicator for adjustment of dosage. Peak concentrations above 12 μg/mL are more likely to be associated with toxicity.
Test Limitations:
Criterion: recovery plus or minus 10% of initial value at concentrations of 3 and 12 μg/mL. Icterus: No significant interference from bilirubin up to an I index of 50 (approximate bilirubin concentration: 50 mg/dL). Hemolysis: No significant interference from hemoglobin up to an H index of 1000 (approximate hemoglobin concentration: 1000 mg/dL). Lipemia: No significant interference from lipemia up to an L index of 1000. Note there is poor correlation between turbidity and triglyceride concentration. No significant interference from total protein up to 13 g/dL or rheumatoid factor up to 1200 IU/mL. As with any assay employing sheep antibodies, the possibility exists for interference by human anti-sheep antibodies in the sample, which could cause unreliable results.
Methodology:
Kinetic Interaction of Microparticles in Solution (KIMS)
CPT Code:
80156
 
See Additional Information:
Chemistry Critical Lab Values