Skip to content

Tacrolimus concentration in plasma (quantitative)

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 plasma. It helps doctors monitor your dose to ensure it stays within safe levels.

Quick summary

["Tacrolimus levels help prevent rejection while minimizing side effects."]

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

Key facts at a glance

LOINC
73133-1
Short code
Tacrolimus ind plt IgG SerPl Ql FC
Synonyms
Tacrolimus ind plt IgG SerPl Ql FC
Category
hematology
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
82784
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 Is This Test Done?

Your doctor may order this test if you’re taking tacrolimus for a transplant, such as a kidney, liver, or heart transplant. Regular monitoring helps adjust your medication to keep your immune system under control without overreacting to the transplant.

What Does the Test Measure?

Tacrolimus is a calcineurin inhibitor used to suppress your immune system after a transplant. The test checks how much of this drug is in your blood plasma, which is crucial for maintaining the right balance to prevent organ rejection.

How Is the Test Performed?

A blood sample is taken from a vein in your arm. The sample is sent to a lab where it’s analyzed to determine the concentration of tacrolimus in your plasma.

What Are Common Results?

There are no standard reference ranges provided here since they vary by lab and patient factors. Your results will be interpreted by your healthcare provider based on your specific medical needs and current medication.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Monitoring tacrolimus levels is critical because it balances the risk of organ rejection with potential side effects like kidney damage or infections. Too little drug may lead to rejection, while too much can cause toxicity. Regular testing ensures your dose is optimized for safety and effectiveness.

Short name

Tacrolimus Level (Plasma)

Frequently asked questions

What does a tacrolimus test measure?
The test measures the amount of tacrolimus, a medication used to prevent organ rejection after a transplant, in your blood plasma.
Why is it important to monitor tacrolimus levels?
Monitoring helps ensure your dose stays within safe limits to prevent organ rejection while reducing side effects like kidney problems or infections.
Can I eat or drink before this test?
You may eat and drink normally unless your doctor instructs otherwise. Some medications, including tacrolimus, can affect results, so check with your provider if you’re unsure about timing.
  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