Quick Facts
- Sample: Blood
- Fasting: Fasting not required, draw as a trough sample right before your next dose
- Turnaround: 2-5 days. May take longer based on weather, holiday, or lab delays.
What This Test Measures
This test measures the concentration of tacrolimus in your blood using a highly sensitive LC/MS/MS methodology. Tacrolimus (also known as FK506, Prograf, or Protopic) is an immunosuppressive drug used to help prevent organ rejection in transplant patients, and this test directly measures the amount of the drug present in your blood at the time of collection.
The result is reported as a quantitative drug concentration, reflecting a trough level drawn right before your next scheduled dose. This measurement helps determine whether your tacrolimus level falls within a therapeutic range, rather than being too low or reaching a potentially toxic level.
Benefits
- Directly measures tacrolimus concentration in your blood
- Uses a highly sensitive LC/MS/MS testing method
- Supports monitoring of therapeutic drug levels over time
- Helps identify levels that may be too low or too high
- Reflects a trough sample drawn before your next dose
- Provides objective data your provider can review
Who Is This Test For?
- Individuals currently prescribed tacrolimus (Prograf, FK506, Protopic)
- Transplant patients receiving tacrolimus for immunosuppression
- People starting tacrolimus therapy who need dosing established
- Individuals whose tacrolimus dosage has recently changed
- People experiencing symptoms that may suggest side effects or toxicity
- Patients being monitored under ongoing care by a healthcare provider
How It Works
- Order Your Test Online
- Visit a Local Lab
- Get Results Online
FAQ
1. What is the purpose of this test?
This test measures the concentration of tacrolimus in your blood using highly sensitive LC/MS/MS methodology, reported as a quantitative value reflecting a trough sample drawn right before your next scheduled dose. It helps a healthcare provider evaluate whether your drug level falls within a therapeutic range or is too low or too high. This test does not diagnose organ rejection or toxicity on its own, and it does not measure other drugs, biomarkers, or organ function markers.
2. Who should get this test, and when?
People currently prescribed tacrolimus for transplant-related immunosuppression may benefit from this test — particularly when starting therapy, after a recent dose change, during ongoing monitoring, or if you experience symptoms that could suggest side effects or toxicity. Ordering and timing decisions should be guided by your healthcare provider managing your care.
3. Do I need to fast before this test?
Fasting is not required for this test. It should be drawn as a trough sample right before your next scheduled dose of tacrolimus.
4. How quickly will I get results?
Results are typically available in 2 to 5 days. Results may take longer based on weather, holiday, or lab delays.
5. How do I interpret the results?
Interpreting your tacrolimus level depends on factors such as your dosing schedule, timing of your last dose, symptoms, medical history, other medications or supplements, and specimen quality. A result outside the expected range does not automatically confirm toxicity or rejection, and a result within range does not rule out a concern. Discuss your results with a qualified healthcare provider familiar with your treatment.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
6. What should I do if my results are abnormal?
If your results fall outside the expected range, review them with a qualified healthcare provider. Do not stop prescribed medication unless instructed by your healthcare provider. Your provider may consider additional evaluation or testing based on your individual situation.
7. How often should I get tested?
Testing frequency depends on your individual treatment plan, particularly during dose adjustments or early therapy. Follow the schedule recommended by your healthcare provider.
Pre-test preparation
Fasting is not required for this test. It should be drawn as a trough sample right before your next scheduled dose of tacrolimus. Do not stop prescribed medication unless instructed by your healthcare provider.
