Tacrolimus (FK506), Blood (LC/MS-MS)

Additional Information:

Specimens from patients who have circulating human antimouse (HAMA) as a result of having received mouse monoclonal antibodies may give falsely elevated or depressed results in this assay.

CPT Code(s):


Specimen Requirements:

  • Container- Lavender top
  • Specimen Type- Whole blood
  • Minimum volume – 1 ml
  • Storage/stability – Refrigerated (2 – 8°C): 14 days
  • Epic order code: Lab876


Tacrolimus is an immunosuppressive drug that is believed to prevent rejection in transplantation patients. Measurement of tacrolimus blood levels may be of use in monitoring patients receiving this drug.


Liquid chromatography/tandem mass spectrometry (LC/MS-MS).

Reference Values:

Clinical studies have shown that patients administered 0.07 mg/kg Prograf® obtain an optimal response to the drug at the following trough levels:
Trough (immediately following transplant): 15.0 ng/mL
Trough (steady-state, two weeks or more after transplant): 3.0−8.0 ng/mL