Sirolimus (Rapamycin) Test

A Sirolimus Blood Test is a test to measure the levels of sirolimus in blood. Sirolimus, also called rapamycin, is a drug that is used to suppress the immune system in people who have had kidney transplants. It is given in combination with other drugs to prevent rejection of transplanted kidneys. Normally, a person's immune system recognizes a transplanted organ as foreign and begins to attack it. However, Sirolimus limits this response and helps to prevent organ rejection by prohibiting activation and production of white blood cells called T-lymphocytes. It also prohibits antibody production.

No special preparation is needed for this test. You can eat and drink water normally. However, for a patient taking sirolimus medicine, the blood sample is collected either 12 hours after the last dose of medicines and prior to the next dose or as per the discretion of the laboratory professional. The health professional may also order other tests to evaluate organ function and blood cell counts because sirolimus may decrease the patient’s platelet count and affect kidney function.

A level that is higher than the established reference range may cause symptoms associated with toxicity. This is marked by: Elevated blood pressure, Sleeplessness, Nausea and vomiting, Fever, headache, Pale appearance, Chest pain, Excessive bleeding

Decreased sirolimus levels may indicate that more sirolimus drug is necessary to achieve a therapeutic dose. However, an inappropriately low level may lead to rejection of the transplanted organ. Depending on the results, your doctor may decide to adjust the dose that you are given.

An alcohol pad is used to clean the skin. A needle is then injected through the part of the rinsed skin into your vein. The blood is then dragged out from the needle by a nozzle, saved in a vessel and sealed with your name. This sample is then sent to the research laboratory for examination.