What happens after I get my results?

You'll receive doctor notes in clear, simple language explaining what your Sirolimus levels mean and whether your current dose is working effectively. These notes include specific guidance on whether your medication needs adjustment, what side effects to watch for, and when you should follow up with your transplant team. Along with your standard lab report, you can track your Sirolimus levels over time using our trends feature, which is especially helpful for seeing how dose changes affect your blood levels.

Who should consider getting this test?

This test is specifically for patients who have received an organ transplant (kidney, liver, heart, or lung) and are taking Sirolimus as an immunosuppressant medication. You'll need regular monitoring if you're newly starting Sirolimus, if your dose has been changed, if you're experiencing possible side effects, or as part of routine follow-up care. Your transplant team will determine how often you need testing based on your individual situation.

What does it mean if my Sirolimus level is too high?

High Sirolimus levels mean you have too much medication in your bloodstream, which increases your risk of side effects like mouth sores, high cholesterol, low blood counts, delayed wound healing, or kidney problems. Your doctor will likely reduce your dose and retest to ensure levels come down to the therapeutic range. It's important not to adjust your medication on your own—always follow your transplant team's instructions.

What does it mean if my Sirolimus level is too low?

Low Sirolimus levels mean there isn't enough medication in your blood to adequately prevent your immune system from rejecting your transplanted organ. This puts you at risk of acute or chronic rejection, which can damage the organ. Your doctor will likely increase your dose and monitor you more closely. Never skip doses or take less medication without consulting your transplant team first.

What can cause my Sirolimus levels to change?

Many factors can affect Sirolimus levels including interactions with other medications, especially certain antibiotics, antifungals, and blood pressure drugs. Grapefruit juice significantly increases Sirolimus levels and should be avoided completely. Changes in diet, liver function, or how consistently you take your medication can also impact levels. Always inform your transplant team about any new medications, supplements, or dietary changes.

How often should I get my Sirolimus levels tested?

Testing frequency depends on your situation. When first starting Sirolimus or after a dose change, you may need testing every few days to weekly until levels stabilize. Once stable, most patients are monitored monthly for the first few months, then every 1-3 months long-term. Your transplant team will create a personalized monitoring schedule based on your stability, how long you've had your transplant, and whether you're experiencing any complications.

What is therapeutic drug monitoring and why is it important for transplant patients?

Therapeutic drug monitoring means measuring medication levels in your blood to ensure the dose is just right—not too high to cause side effects, and not too low to risk organ rejection. Sirolimus has a narrow therapeutic window, meaning the difference between an effective dose and a harmful dose is small. Everyone metabolizes medications differently, so monitoring helps personalize your treatment and gives you the best chance of maintaining a healthy, functioning transplant for years to come.

Can I do anything to help keep my Sirolimus levels stable?

Take your Sirolimus at the same time every day, consistently with or without food (whichever way you started). Avoid grapefruit and grapefruit juice entirely, as they dramatically increase drug levels. Keep a medication diary and never skip doses. Tell all your doctors that you take Sirolimus before starting any new medications or supplements. Store your medication properly according to the label instructions, and attend all scheduled monitoring appointments so your transplant team can catch any issues early.