Tacrolimus, Peak, Blood
Use
Tacrolimus (Prograf) is a macrolide antibiotic derived from the fungus Streptomyces tsukubaensis. It is used to suppress T cell activity by inhibiting calcineurin, which is necessary to manage immunosuppression in transplant patients. Due to its narrow therapeutic window and individual pharmacokinetic variability, therapeutic drug monitoring of tacrolimus is critical to ensuring efficacy while minimizing toxicity. Monitoring postdosing blood concentrations helps optimize dosing to prevent organ rejection and manage side effects, particularly nephrotoxicity.
Special Instructions
This test should be ordered for specimens collected during a peak period postdose. Date of last dose, time of last dose, and dosage information are required to accompany the specimen. Forms such as the Therapeutics Test Request should be completed if not ordered electronically.
Limitations
Established reference ranges for tacrolimus reflect trough measurement and may not apply to specimens collected after dosing. This test specifically measures postdose levels, and results should be interpreted within the context of clinical information, such as time since transplant and type of organ grafted. The assay is specific to tacrolimus and does not cross-react with cyclosporine or its metabolites, sirolimus, or its metabolites.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 59822-7
- 59822-7
- 29742-4
- 29637-6
- 32594-4
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
3 mL
Minimum Volume
1 mL
Container
Lavender top (EDTA)
Collection Instructions
Do not centrifuge. Send whole blood specimen in original tube. Do not aliquot.
Causes for Rejection
Clotted specimen
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |