Carbamazepine, Free and Total, Serum
Use
The test is useful for monitoring carbamazepine therapy (free and total) in patients, particularly those who are uremic. Carbamazepine is effective for complex partial seizures and is often used with other antiepileptic drugs like phenytoin and valproic acid. Monitoring the free fraction of carbamazepine, which may be displaced in uremic conditions, helps in accurately adjusting the dosage as both neurological activity and toxicity are related to the circulating free portion of the drug.
Special Instructions
If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen. To ensure fresh serum, centrifuge and aliquot into a plastic vial within 2 hours of collection.
Limitations
Fresh serum with normal protein content is necessary to prevent analytical errors due to protein denaturation. Specimens with significant heat exposure or high levels of hemolysis, lipemia, or icterus may be non-viable for testing, leading to cancellation of the assay due to interference beyond acceptable analytical thresholds.
New York Approved
Methodology
Immunoassay (Homogeneous Microparticle Agglutination)
Biomarkers
LOINC Codes
- 34545-4
- 3432-2
- 3433-0
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
2 mL
Minimum Volume
1 mL
Container
Plastic vial
Collection Instructions
Centrifuge and aliquot serum into a plastic vial within 2 hours of collection.
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 48 hours |
| Refrigerated | 7 days |
| Frozen | 28 days |