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Sirolimus LC-MS/MS

Test Code: 30407
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Clinical and Procedure
Clinical Utility

Sirolimus is an immunosuppressant that inhibits IL-2 and blocks activation of T cells.  It is primarily used to prevent rejection post kidney transplant due to its low toxicity. It is metabolized by the CYP3A4 enzyme with a ~57-63 hour half-life. Intestinal absorption varies widely.  The Sirolimus LC-MS/MS assay is used to quantify levels of Sirolimus in the blood.  In some cases, patients have had in vivo drug levels up to eight times greater  than other patients who were receiving the same dosage. Often use is recommended with cyclosporine and corticosteroids.

About Immunosuppressive Drug Level Monitoring

The successful management of transplant rejection and graft vs. host disease (GVHD) continues to pose a difficult challenge for physicians treating solid organ and bone marrow transplant patients. Immunosuppressive drugs are commonly used to prevent rejection in these patient populations. Compliance with immunosuppressive therapy is essential to long term survival, however provides the additional risks of infection. Therapeutic drug monitoring of immunosuppressive medication is required due to variable metabolism, absorption and drug interactions. By using drug level monitoring with timely results, the physician is able to individualize drug dosage to improve efficacy and reduce toxicity.


Sirolimus is extracted from whole blood by simple protein precipitation with Zinc Sulfate Solution followed by centrifugation. Chromatographic separation and quantitative analysis of the drug containing supernatant is performed using reversed-phase UPLC-MS/MS method. This test has not been cleared or approved for diagnostic use by the U.S. Food and Drug Administration.


Compound is identified by two mass transitions. The first mass transition is used to quantify the compound and the second is qualitative for confirmation. Test is specific for Sirolimus and does not cross react with other immunosuppressants.

Turnaround Time

Same day (within 12-18 hours from receipt of specimen), Monday through Saturday.

Specimen Information
Specimen Type Test Code CPT Code NY Approved Volume Assay Range Special Instructions
whole blood 30407 80195 Yes

2 mL (min. 0.5 mL)

Assay range varies by lot.

  • Collect in EDTA tube
  • Specimens shipped at ambient temperature must be received within 7 days of collection
  • Stability: 7 days ambient, 14 days refrigerated, 14 days frozen

Ship Monday through Friday. Friday shipments must be labeled for Saturday delivery. All specimens must be labeled with patient's name and collection date. A Viracor Eurofins test requisition form must accompany each specimen. Multiple tests can be run on one specimen. Ship specimens FedEx Priority Overnight® to: Viracor Eurofins, 18000 W 99th St. Ste, #10, Lenexa, KS 66219.

Causes for Rejection

Specimens received outside stability, whole blood collected in serum or plasma gel tubes, or specimen types other than those listed are not accepted.


Specimens are approved for testing in New York only when indicated in the Specimen Information field above. The CPT codes provided are based on Viracor Eurofins' interpretation of the American Medical Association's Current Procedural Terminology (CPT) codes and are provided for informational purposes only. CPT coding is the sole responsibility of the billing party. Questions regarding coding should be addressed to your local Medicare carrier. Viracor Eurofins assumes no responsibility for billing errors due to reliance on the CPT codes illustrated in this material.

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