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Test Code Billings Clinic: 4036 Tegretol® (Carbamazepine), Plasma or Serum

Important Note

This test can not be added on to a specimen that is already in the lab.  A new sample must be drawn.

Patients taking therapeutic levels of cetirizine or hydroxyzine may have falsely elevated levels of Carbamazepine.

Performing Laboratory

Billings Clinic Laboratory: Chemistry

Useful For

  • Monitoring therapy
  • Determining compliance
  • Assessing toxicity

Methodology

Particle-enhance turbidimetric inhibition immunoassay (PETINIA)

Specimen Requirements

Submit only 1 of the following specimens:
Serum or plasma should be physically separated from cells as soon as possible with a maximum limit of two hours from the time of collection.

 

Plasma

  • Draw blood in a green-top (lithium heparin) tube(s).
  • Spin down and send 1.0 mL of heparinized plasma in plastic vial, refrigerated
  • Date and time of last dose and date and time of draw are required on request form for processing.
  • Indicate plasma on request form.
  • Label specimen appropriately (plasma).

 

Serum

  • Draw blood in a plain, red-top tube(s) or a serum gel tube(s).
  • Spin down and send 2 mL of serum refrigerated. 
  • Date and time of last dose and date and time of draw are required on request form for processing.
  • Indicate serum on request form.
  • Label specimen appropriately (serum).

Storage/Stability

Specimen Type Temperature Time
Serum, Plasma Refrigerated (preferred) 2 days
  Frozen 1 month
  Ambient 8 hours

 

Reject Due To

  • Gross hemolysis
  • Gross lipemia

Reference Values

  • Therapeutic concentration:  4.0 - 12.0 µg/mL
  • Call-back toxic concentration level:  >12.0 µg/mL

Day(s) Test Set Up

Daily

Test Classification and CPT Coding

80156 - Carbamazepine; total

LOINC Code Information

Reporting Name LOINC Code
Tegretol 3432-2
Last Dose 45285-4