Therapeutic Drug MonitoringTransplant Medicine

Tacrolimus Levels

Normal Range
5.0 - 20.0 ng/mL (Target range varies by organ and time post-transplant)
Sample Type
Whole Blood
Fasting
No
Unit
ng/mL

Function

Tacrolimus (Prograf) is a potent calcineurin inhibitor used as an immunosuppressant. It prevents the body from rejecting transplanted organs (kidney, liver, heart, etc.) by inhibiting T-lymphocyte activation. Because it has a narrow therapeutic index, blood levels must be monitored precisely to balance efficacy with toxicity.

Why it is Ordered

Monitoring is essential to ensure the drug concentration is high enough to prevent organ rejection but low enough to avoid serious side effects like nephrotoxicity or neurotoxicity. It is ordered frequently immediately after transplant and periodically throughout the patient's life.

Associated Conditions

  • Organ Transplantation: Post-operative management for kidney, liver, or heart recipients.
  • Graft-versus-Host Disease (GVHD): Prevention in bone marrow transplant patients.
  • Nephrotoxicity Monitoring: Assessing if kidney damage is caused by the drug itself.

Check Your Result

Check Your Result

Interactive
ng/mL

Enter your lab result to see where you stand compared to the standard reference range.

Why Context Matters

The timing of the blood draw is the most critical confounding factor; it must be a 'trough level' (taken exactly before the next dose). If the sample was drawn shortly after taking the medication, the result will be falsely elevated. Additionally, tacrolimus binds heavily to red blood cells, so hematocrit variations or liver function changes can alter the interpretation of 'free' drug levels. Certain foods (grapefruit) and medications (CYP3A4 inhibitors/inducers) significantly alter metabolism.

Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.

Clinical References

Source-of-truth databases and clinical guidelines for Tacrolimus Levels:

Research & Guidelines

Related Indicators

Lithium

View Range
DR

Medically Reviewed by Dr. Binoy Babu, MBBS

Board Certified Doctor • 10+ Years Clinical Experience

Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.

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