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Blood Test Tracker

Everolimus

Shows how much everolimus, a medicine used after transplants and for some tumors, is in your blood, so your team can fine-tune your dose.

AI-verified against cited sources. Awaiting expert reviewLOINC 50544-6

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What it is

Everolimus is a prescription medicine that blocks a protein called mTOR. It is sold as Zortress, to help prevent rejection of a transplanted kidney or liver, and as Afinitor, for certain cancers and for tuberous sclerosis complex (TSC). Outside the US it is also sold as Certican. This test measures how much of the drug is in whole blood. The sample is usually a trough, drawn just before your next dose, when the level is lowest.

Why it matters

The right amount can be hard to hit. Too little may not protect a transplanted organ or control a condition. Too much can add to side effects, such as mouth sores, infections, high cholesterol and triglycerides, and protein in the urine. The Zortress label notes that the risk of protein in the urine is higher at higher trough levels. Your team uses this result, along with tests like kidney function, to decide whether your dose is right.

If it’s low

A level below your target means less of the drug is in your blood than your team aimed for. For a transplant, that may mean less protection against rejection. A recent dose change can also show a low number until the level has had a few days to settle.

Common causes

  • Missed or late doses
  • Medicines or herbal products that speed up how the body clears everolimus, such as rifampin, some seizure medicines and St. John's wort
  • Vomiting or diarrhea soon after a dose
  • A sample drawn at a different point in the dosing cycle than usual
  • A dose change in the last few days, before the level has settled

What can help

  • Tell your care team about missed doses, vomiting or diarrhea
  • Ask your care team before starting any new medicine or herbal product
  • Ask your care team which dosing schedule is right for you, and keep to it

If it’s high

A level above your target means more of the drug is in your body than your team aimed for. This can happen even when you take your doses exactly as prescribed. For transplant use, the Zortress label says to adjust the dose when the trough is above 8 ng/mL on two checks in a row. Only your care team should make that change.

Common causes

  • Medicines that slow how the body clears everolimus, such as some antifungal medicines (for example ketoconazole) and certain antibiotics
  • Grapefruit or grapefruit juice
  • Reduced liver function (the label lowers the starting dose in mild liver impairment)
  • A sample drawn after the dose instead of just before it
  • Taking doses closer together than intended
  • Differences between lab methods, since results from different assays may not match

What can help

  • Tell your care team about every medicine, supplement and food you use, including grapefruit juice
  • Ask whether your level should be rechecked, and how soon
  • Check with your care team before changing or skipping any dose

Usual ranges

What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.

For adults: 3–8 ng/mL. Source: Novartis Pharmaceuticals, via DailyMed (NIH National Library of Medicine), ARUP Laboratories.

What can affect your result

  • Timing of the blood draw relative to your last dose
  • The lab method used (LC-MS/MS or immunoassay)
  • Other medicines, including cyclosporine, tacrolimus, antifungals, some antibiotics and some seizure medicines
  • Grapefruit and grapefruit juice
  • Liver function
  • How consistently you take your doses
  • Time since your last dose change
  • Different lab methods (LC-MS/MS or immunoassay) can give different numbers for the same sample, and the label says results from different assays may not be interchangeable.
  • A sample drawn after the dose is not a trough and will read higher.
  • The sample is whole blood collected in an EDTA (lavender-top or pink-top) tube, as ARUP specifies. Serum or plasma tubes are not used.

Trough sample: drawn just before your next scheduled dose, at the same point in your dosing cycle each time. About 4 to 5 days to settle at a new level after a dose change. The Zortress label bases dose changes on troughs drawn 4 or 5 days after the last change. The Afinitor label for TSC suggests checking a trough 1 to 2 weeks after a dose change.

When to talk to a clinician

There is no widely used critical limit for everolimus. Call your transplant or care team the same day if the lab flags your result, if it is well outside the target they gave you, or if you have fever, chills, a new cough, trouble breathing, mouth sores that won't heal, swelling, or a wound that heals slowly. If you have trouble breathing, swelling of the face or throat, or chest pain, call 911 or your local emergency number.

Questions you could ask

  • Will my blood always be drawn at the same time relative to my dose?
  • Is the same lab and method used each time?
  • What level am I aiming for, and why?
  • Could any of my other medicines or foods be raising my level?
  • Should we recheck my level soon, and should my kidney function and urine protein be checked too?
  • Could a missed dose or a new medicine explain a low level?

Questions people ask

Why is my target range different from someone else's?

The target depends on why you take everolimus and what you take with it. The Zortress label sets 3 to 8 ng/mL for transplant use alongside reduced doses of cyclosporine or tacrolimus. The Afinitor label sets 5 to 15 ng/mL for TSC. Your care team chooses yours.

Why does the blood draw need to happen before my dose?

A trough is the lowest level of the cycle, just before the next dose. Drawing at the same point each time lets your team compare results fairly. A sample taken after a dose reads higher and can look like a problem that isn't there.

Can I compare results from two different labs?

Not always. Different lab methods can give different numbers for the same sample, and the 3 to 8 ng/mL transplant target was set using LC-MS/MS. If you can, use the same lab and method each time.

Show the science and sources

Units

  • 1 ng/mL = 1 ng/mL
  • 1 ng/mL = 1.044 nmol/L

Open the Everolimus unit converter

For clinicians and researchers

Everolimus is the 40-O-(2-hydroxyethyl) derivative of sirolimus and an mTOR inhibitor. It is a CYP3A4 and P-glycoprotein substrate. In adult kidney-transplant patients the half-life was 30 ± 11 hours (range 19 to 53), and the Zortress label bases dose changes on troughs drawn 4 to 5 days after a change. Whole-blood EDTA is the matrix. The 3 to 8 ng/mL transplant target was defined with LC-MS/MS and with reduced-exposure cyclosporine or tacrolimus; the label cautions that chromatographic and immunoassay results may not be interchangeable and that the assay used should be known. In TSC-associated SEGA and seizures, the Afinitor label titrates to a trough of 5 to 15 ng/mL. Ketoconazole raised everolimus AUC about 15-fold in healthy subjects, and strong CYP3A4 or P-gp inducers lower exposure. Proteinuria risk rises with higher troughs. ARUP's directory lists a toxic value above 15 ng/mL, but everolimus is not on ARUP's critical-values list, and a 2026 survey found it on only about 10% of US hospital critical lists (median limit 15 ng/mL), so this entry carries no critical limit.

LOINC 50544-6 (primary), 77349-9. Specimen: whole-blood.

Sources

  1. ZORTRESS (everolimus) tablets: prescribing information, Novartis Pharmaceuticals, via DailyMed (NIH National Library of Medicine) (2026)
  2. AFINITOR and AFINITOR DISPERZ (everolimus) tablets: prescribing information, Novartis Pharmaceuticals, via DailyMed (NIH National Library of Medicine) (2026)
  3. Everolimus by Tandem Mass Spectrometry (ARUP test 0092118), ARUP Laboratories

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.

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