Quantitation of sirolimus level in whole blood
Monitoring whole blood sirolimus concentration during therapy. May be especially useful for individuals also
administered CYP3A4 substrates, inhibitors, or inducers.
Collection Processing Instructions:
1. Draw blood immediately before a scheduled dose.
2. Do not centrifuge.
3. Send specimen in original tube. Do not aliquot. Aliquots will be rejected.
Trough (ie, sample drawn immediately before a scheduled dose) Sirolimus concentrations are generally measured every 5 days. Blood drawn at other times will yield higher results
Most individuals display optimal response to sirolimus with trough whole blood levels 4.0 to 20.0 ng/mL. Preferred therapeutic ranges may vary by transplant type, protocol, and co-medications. Target concentrations vary depending on concomitant therapy, time post-transplant, the desired degree of immunosuppression, and adverse effects. When given with cyclosporine or tacrolimus, the therapeutic range for sirolimus is generally between 4 and 12 ng/mL, with minimal added benefit for concentrations >10 ng/mL. When sirolimus is given without calcineurin inhibitors, higher trough levels are needed; usually 12 to 20 ng/mL, but occasionally up to 20 to 30 ng/mL.
The assay is specific for sirolimus; it does not cross-react with tacrolimus, everolimus, cyclosporine, or any of their metabolites.
This test was developed and its performance characteristics determined by Marshfield Labs. It has not been cleared or approved by the US Food and Drug Administration. This test is used for clinical purposes. It should not be regarded as investigational or for research.