ARUP's Laboratory Test Directory

Tacrolimus by Tandem Mass Spectrometry : 0090612

Mnemonic: TACRO

Methodology: Quantitative Liquid Chromatography-Tandem Mass Spectrometry
Performed: Sun-Sat
Reported: Within 24 hours
Specimen Required: Patient Prep: Pre-dose (trough) levels should be drawn.

Collect: Lavender (EDTA) or pink (K2EDTA).

Specimen Preparation: Transport 1 mL whole blood. (Min: 0.25 mL)

Storage/Transport Temperature: Refrigerated.

Unacceptable Conditions: Serum or plasma. Specimens left at room temperature for longer than 24 hours. Clotted specimens.

Stability (collection to initiation of testing): Ambient: 24 hours; Refrigerated: 2 weeks; Frozen: 2 months

Reference Interval:
Therapeutic Range:
Kidney and Liver:
0-2 months post-transplant: 10.0-15.0 ng/mL
3 months and older: 5.0-10.0 ng/mL

Heart:
0-2 months post-transplant: 10.0-18.0 ng/mL
3 months and older: 8.0-15.0 ng/mL
Toxic alert value: Greater than 25 ng/mL
Interpretive Data: Therapeutic range is based on a whole blood specimen drawn 12 hours post-dose or prior to next dose (the trough). Some other factors influencing therapeutic range, dose administered, and result interpretation include time since transplantation, the organ transplanted, co-administration of other immunosuppressants, interaction with other drugs that may increase or decrease the tacrolimus concentration, and the preferences of the transplant centers and clinicians.

See Compliance Statement B: www.aruplab.com/CS
Note: Tacrolimus (Prograf®) whole blood concentrations can be measured by either chromatographic or immunoassay methodologies.  These two methodologies are not directly interchangeable, and the measured tacrolimus whole blood concentration depends on the type of assay used.  Reference ranges may vary according to the specific immunoassay or LC/MS/MS test used. Generally, immunoassays have been reported to have a positive bias relative to the reference assay, HPLC with detection by tandem mass spectrometry (LC/MS/MS). 
CPT Code(s): 80197
Cross References: FK506 (Tacrolimus by Tandem Mass Spectrometry), Prograf® (Tacrolimus by Tandem Mass Spectrometry) , Protopic (Tacrolimus by Tandem Mass Spectrometry)