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Tacrolimus (whole blood) concentration

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of tacrolimus, a medication used to prevent organ rejection after a transplant, in your blood.

Quick summary

["Your blood level helps doctors monitor how well your body is responding to this medication."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
11253-2
Short code
Tacrolimus Bld-mCnc
Synonyms
Tacrolimus Bld-mCnc
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Doctors order tacrolimus blood tests to ensure you’re taking the right dose of this medication. It helps prevent your immune system from attacking the transplanted organ and reduces the risk of rejection. Levels are checked regularly, especially after starting the medication or if you’re adjusting your dose.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm or hand to draw a blood sample. It usually takes a few minutes. If you’re on this medication long-term, your doctor may schedule tests at consistent intervals to track your levels.

What the Results Mean

Results help doctors determine if your dose is too high or too low. High levels may cause side effects like nausea, headaches, or kidney problems. Low levels might mean your immune system isn’t being controlled properly. Your doctor will discuss these findings with you.

Common Side Effects of Tacrolimus

Tacrolimus can cause side effects like nausea, dizziness, or increased sensitivity to sunlight. Long-term use may affect your kidneys or increase your risk of infections. Your doctor will monitor these effects while managing your medication.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Tacrolimus Blood Level

Frequently asked questions

How often will I need this test?
Your doctor will decide the frequency based on your transplant type, health, and how well you’re responding to the medication. Some patients need tests weekly at first, then less often as they stabilize.
Can I eat or drink before the test?
You can eat and drink normally before the test, as it doesn’t require fasting. However, always follow your doctor’s instructions for any specific preparations.
What happens if my levels are too high?
If levels are too high, your doctor may adjust your dose downward to avoid side effects like kidney damage or increased risk of infections. They’ll work with you to find the right balance.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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