Test Code Billings Clinic: 8778 Mayo: TAKRO Tacrolimus, Blood
Reporting Name
Tacrolimus, BPerforming Laboratory
Mayo Clinic Laboratories in RochesterUseful For
Monitoring whole blood tacrolimus concentration during therapy, particularly in individuals coadministered cytochrome P450 (CYP) 3A4 substrates, inhibitors, or inducers
Adjusting dose to optimize immunosuppression while minimizing toxicity
Evaluating patient compliance
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Specimen Required
Container/Tube: Lavender top (EDTA)
Specimen Volume: 3 mL
Collection Instructions:
1. Draw blood immediately before a schedule dose.
2. Do not centrifuge.
3. Send whole blood specimen in original tube. Do not aliquot.
Additional Information: Therapeutic range applies to trough specimens collected immediately prior to a.m. dose.
Specimen Type
Whole Blood EDTASpecimen Minimum Volume
1 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Whole Blood EDTA | Refrigerated (preferred) | 14 days | |
Ambient | 14 days | ||
Frozen | 14 days |
Reject Due To
Gross hemolysis | OK |
Gross lipemia | OK |
Gross icterus | OK |
Clotted specimens | Reject |
Reference Values
5.0-15.0 ng/mL (Trough)
Target steady-state trough concentrations vary depending on the type of transplant, concomitant immunosuppression, clinical/institutional protocols, and time post-transplant. Results should be interpreted in conjunction with this clinical information and any physical signs/symptoms of rejection/toxicity.
Interpretation
Most individuals display optimal response to tacrolimus with trough whole blood levels of 5.0 to 15.0 ng/mL. Preferred therapeutic ranges may vary by transplant type, protocol, and comedications.
Therapeutic ranges are based on specimen collected at trough (ie, immediately before a scheduled dose). Higher results will be obtained when the blood is drawn at other times.
The assay is specific for tacrolimus; it does not cross-react with cyclosporine, cyclosporine metabolites, sirolimus, sirolimus metabolites, or tacrolimus metabolites. Results by liquid chromatography with detection by tandem mass spectrometry are approximately 30% less than by immunoassay.
Day(s) Performed
Monday through Sunday
Report Available
Same day/1 to 3 daysTest Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
80197
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
TAKRO | Tacrolimus, B | 77348-1 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
35145 | Tacrolimus, B | 77348-1 |
Forms
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-General Request (T239)
-Renal Diagnostics Test Request (T830)
-Therapeutics Test Request (T831)