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Rifabutin concentration in serum/plasma (quantitative)

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

This test measures the amount of rifabutin, a medication used to treat tuberculosis and certain fungal infections, in your blood.

Quick summary

["Rifabutin levels help ensure your dose is appropriate for your body and to monitor for potential side effects."]

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

Key facts at a glance

LOINC
42655-1
Short code
Rifabutin Islt Slgr Mcbct AB 0.5
Synonyms
Rifabutin Islt Slgr Mcbct AB 0.5
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
method-for-slow-growing-mycobacteria-antibiotic-concentration-at-ug-ml
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 Is Done

Your healthcare provider may order this test if you’re taking rifabutin to treat an infection or to check if your body is processing the medication correctly. It’s especially important if you have liver problems or are taking other medications that interact with rifabutin.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for a few hours before the blood draw if your test is part of a broader metabolic or liver assessment.

What the Test Results Mean

Results help determine if your rifabutin levels are within the target range for your condition. Too low levels may mean your dose isn’t working, while too high levels could indicate side effects like liver damage.

Common Reasons for Monitoring

This test is often used in patients with tuberculosis, HIV, or fungal infections to adjust rifabutin doses safely and avoid complications like drug resistance or toxicity.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Rifabutin Level

Frequently asked questions

Why might my rifabutin levels be checked regularly?
Regular monitoring helps ensure your dose stays safe and effective, especially if you have liver issues, take other medications, or if your infection requires long-term treatment.
What happens if my rifabutin levels are too high?
High levels may cause side effects like nausea, liver damage, or rash. Your provider may adjust your dose or switch medications if needed.
Can I eat or drink before this test?
No special diet is required, but follow your provider’s instructions if this test is part of a broader evaluation (e.g., fasting for other tests).
  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