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Test Code TEGX or LAB21 Carbamazepine Level, Total, Serum or Plasma

Important Note

For information on draw times, please call Bronson lab client services at 269-341-6440.

For general guidelines on therapeutic drug monitoring (TDM), please see the TDM general guidelines document. 

Specimen Requirements

Container Type:

Optimal: Gold or Mint*

*For STAT requests

Acceptable: Red or Green
Optimal Collection Volume: 

4.5mL; full tube
Minimum Volume:
  • Adults: 1 mL whole blood
  • Neonates: 1 microtainer (400-600 uL)
Collection Instructions:

Gently invert the sample 5-6 times after collection.
Specimen Transport:

Refrigerate
Processing Instructions: 

1. If serum, allow the specimen to clot for 30 minutes.

2. Centrifuge specimen within 2 hours of collection.

3. After centrifugation, specimen tubes without a gel barrier should have the serum or plasma aliquoted to a false bottom container.

4. Keep the serum or plasma refrigerated until testing can be performed.

Specimen Stability

Specimen Type Temperature Time
Serum* Refrigerated 7 days
Room Temperature 2 days
Frozen 4 weeks

*Note: Heparinized plasma in gel separator tubes is less stable than serum and is only suitable for add-on testing up to 2 days following sample collection.

Specimen Rejection Criteria

Hemolysis Mild OK; Moderate OK; Gross Reject
Lipemia Mild OK; Moderate OK; Gross Reject
Icterus Mild OK; Moderate OK; Gross Reject
Other Quantity not sufficient

Useful For

Monitoring therapeutic concentrations of Carbamazepine (Tegretol).

Methodology

Roche Cobas - Homogeneous microparticle agglutination immunoassay

Reference Ranges

Therapeutic range: 4-12 ug/mL

 

Critical Value: > 20 ug/mL

Interpretive

Equivalent diagnostic technologies have shown that in most adults receiving carbamazepine as the sole antiepileptic agent, a peak therapeutic response is achieved with levels between 8-12 µg/mL. Lower concentrations may provide an effective therapeutic response when other anticonvulsants are used in combination with carbamazepine. Serum or plasma level monitoring provides an indicator for individual dosage regimens. Some patients may require levels outside these ranges for effective treatment. 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 dosage adjustment.

Day(s) Performed

24/7

Expected TAT

Same day

Performing Laboratory

Bronson Laboratory, Chemistry - Kalamazoo and Battle Creek

Sample Retention Time

7 days

CPT Code

80156

LOINC Code

3432-2