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Rifampin Drug Concentration (Serum/Plasma)

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

This test measures the amount of rifampin, an antibiotic used to treat certain infections like tuberculosis, in your blood.

Quick summary

["Understanding your rifampin levels helps ensure the medicine is working effectively and safely."]

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

Key facts at a glance

LOINC
25204-9
Short code
rifAMPin Islt Slgr Mcbct AB 5.0
Synonyms
rifAMPin Islt Slgr Mcbct AB 5.0
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 rifampin to check if the dose is appropriate for your condition. It helps monitor how well the drug is working and whether you’re experiencing side effects.

What to Expect Before the Test

No special preparation is needed. You’ll likely have a small needle inserted into your arm to draw blood. The process is quick and usually painless.

What the Results Mean

Results help determine if your rifampin levels are within the target range for your treatment. Too low may mean the drug isn’t working, while too high could increase side effects.

Common Uses and Considerations

Rifampin is often used for tuberculosis or other bacterial infections. Your provider may adjust your dose based on these results to avoid resistance or toxicity.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Rifampin levels are critical for managing infections like tuberculosis, as improper dosing can lead to treatment failure or drug resistance. Your provider will use these results to tailor your care.

Short name

Rifampin Level

Frequently asked questions

Why might I need this test?
You may need this test if you’re taking rifampin to treat an infection, or if your provider wants to check how well the drug is working in your body.
What does a low or high rifampin level mean?
A low level might mean the drug isn’t reaching the right amount in your blood, while a high level could indicate side effects or the need for dose adjustments.
Can I eat or drink before the blood test?
You can eat and drink normally before the test, as it doesn’t require fasting.
  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