{"id":"tacrolimus","name":"Tacrolimus","shortName":"Tacrolimus","aliases":["Tacrolimus, Whole Blood","Tacrolimus Level","Tacrolimus Trough","Tacrolimus, Blood","Tacrolimus, Highly Sensitive, LC/MS/MS","Tacrolimus by LC/MS/MS","FK506","FK-506","Prograf","Envarsus XR","Envarsus","Astagraf XL","Astagraf"],"abbreviations":["TAC","FK506"],"loinc":[{"code":"11253-2","primary":true},{"code":"77348-1","primary":false},{"code":"74097-7","primary":false},{"code":"74096-9","primary":false},{"code":"76494-4","primary":false}],"specimen":"whole-blood","units":[{"ucum":"ng/mL","display":"ng/mL"},{"ucum":"nmol/L","display":"nmol/L"}],"referenceRanges":[{"population":"Adults","low":5,"high":20,"unit":"ng/mL","unitDisplay":"ng/mL","note":"A broad span, not a personal target. It is the lowest and highest value in ARUP's published trough ranges for twice-daily tacrolimus by LC/MS/MS (kidney 7.0–20.0 ng/mL in the first 3 months and 5.0–15.0 after; heart 10.0–20.0 then 5.0–15.0; liver 5–20 in the first year). Prograf labeling gives matching figures and adds lung 10–15 in months 1–3 and 8–12 after. Labeling also lists lower targets for some regimens, such as 4–11 ng/mL for kidney transplant with mycophenolate and an IL-2 receptor antagonist, and once-daily products have their own targets. ARUP notes the best range for a person depends on the reason for treatment, the treatment phase, other medicines, the time of the draw, the organ and the transplant center's approach.","sources":[{"title":"Tacrolimus by Tandem Mass Spectrometry (test 0090612)","url":"https://ltd.aruplab.com/Tests/Pub/0090612","publisher":"ARUP Laboratories"},{"title":"Prograf (tacrolimus) prescribing information","url":"https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=7f667de1-9dfa-4bd6-8ba0-15ee2d78873b","publisher":"DailyMed, National Library of Medicine"},{"title":"Envarsus XR (tacrolimus extended-release tablets) prescribing information","url":"https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=de2315b0-6344-43ac-9aea-3e3b68d828e7","publisher":"DailyMed, National Library of Medicine"},{"title":"Astagraf XL (tacrolimus extended-release capsules) prescribing information","url":"https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=550a5cd4-fbf2-4c09-b577-6bde8fcbdf6e","publisher":"DailyMed, National Library of Medicine"}]}],"review":{"status":"ai-verified","label":"AI-verified against cited sources. Awaiting expert review","lastReviewed":"2026-10-03"},"summary":"The amount of the anti-rejection medicine tacrolimus in your blood just before your next dose, used by your transplant team to fine-tune treatment.","url":"https://bloodtesttracker.com/markers/tacrolimus","notice":"Information, not medical advice. Ranges differ between labs, so the range on your own report is the one your result is judged against."}