Tacrolimus (Serum) Mass Concentration
This test measures the amount of tacrolimus, a medication used to prevent organ rejection after a transplant, in your blood serum. It helps doctors monitor your dose to ensure it stays within safe levels.
["Your medication levels must be carefully balanced to avoid side effects or rejection."]
Key facts at a glance
- LOINC
- 32721-3
- Short code
- Tacrolimus SerPl-mCnc
- Synonyms
- Tacrolimus SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Matters
Tacrolimus is a powerful immunosuppressant, meaning it lowers your immune system’s ability to fight infections or reject a transplanted organ. Too much can increase your risk of infections or organ damage, while too little may lead to rejection. Regular monitoring ensures your dose is optimized for safety and effectiveness.
How the Test Works
Your blood sample is tested using a specialized laboratory method to detect and quantify the exact amount of tacrolimus in your serum. The result helps your healthcare provider adjust your medication as needed.
What to Expect Before the Test
No special preparation is usually required, but you may need to fast for 8 hours before the test if instructed by your doctor. Wear comfortable clothing for easy blood draw access.
What to Expect During the Test
A healthcare professional will insert a small needle into your arm to draw blood. You may feel a slight pinch, but the process is quick. The blood sample is then sent to the lab for analysis.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Tacrolimus Level
Frequently asked questions
Your tacrolimus level is critical for transplant patients. Low levels may mean your immune system is too active, risking organ rejection, while high levels can weaken your immune system, increasing infection risk. Regular monitoring helps prevent these extremes.
What do my results mean? If your results are outside the target range (provided by your doctor), it may require a dose adjustment. Always discuss results with your healthcare provider.
Is there any risk or discomfort with this test? The blood draw is generally safe but may cause mild discomfort or bruising. Rarely, there could be allergic reactions to the needle or blood loss, though serious complications are uncommon.
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy