Carbamazepine

Label Mnemonic:	CBZ
Epic code:	LAB22
Order form:	Laboratory Requisition
Supply order:	Supply Order Form
Billing:	Billing Policies
CPT code:	80156

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)

Sample Processing:

Centrifuge at a speed and time necessary to get barrier separation of plasma/serum and cells within 1 hour of collection. Send specimen in original tube. Do Not transfer to another tube.
Each sample must be labeled with at least TWO full patient identifiers (First/Last Name & DOB are sufficient for non-UIHC affiliated clients) to avoid sample rejection/delays.

Sample Storage:

Refrigerate.
All sample storage requirements are intended for delivery to UIHC within 24 hours of collection for testing. If samples won't arrive in this time period, please call the UIHC Core Lab for alternative storage/shipping instructions (319-356-3527).

Transport Instructions:

Place labeled specimen into zip-lock type biohazard bag; seal bag.
Place completed requisition into outside pocket of bag.
Transport in cooler with refrigerated coolant packs.

CPT Code:

80156

See also:
Carbamazepine Epoxide & Total Drug Level, Serum

See Additional Information:
Chemistry Critical Lab Values