Carbamazepine

Label Mnemonic:	CBZ
Epic code:	LAB22
Downtime form:	A-1a Doctor/Provider Orders - Pathology Core and Specialty Care Nursery

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 also:
Carbamazepine Epoxide & Total Drug Level, Serum

See Additional Information:
Chemistry Critical Lab Values