Skip to content

Rifampin Drug Concentration in Serum (Quantitative)

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

This test measures the amount of the antibiotic rifampin in your blood serum to check if it’s working properly and at the right level.

Quick summary

["Rifampin helps treat certain bacterial infections but must stay within safe levels to avoid side effects."]

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

Key facts at a glance

LOINC
25203-1
Short code
rifAMPin Islt Slgr Mcbct AB 2.0
Synonyms
rifAMPin Islt Slgr Mcbct AB 2.0
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 doctor may order this test if you’re taking rifampin for a bacterial infection, such as tuberculosis or meningitis. It helps ensure the medication is effective and not causing harmful buildup in your blood.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or hand to draw a blood sample. It usually takes a few minutes, and you may feel a slight pinch.

What the Results Mean

Results help doctors monitor how rifampin is working in your body. Low levels may mean the dose isn’t strong enough, while very high levels could signal side effects or poor absorption.

Possible Side Effects

Rifampin can cause mild side effects like nausea, red/orange urine/tears, or rash. If you experience severe reactions (e.g., allergic reactions, liver issues), contact your doctor immediately.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Rifampin Level

Frequently asked questions

How often should I get this test?
Your doctor will determine the timing based on your treatment plan, but it’s often done during the first few weeks of therapy and sometimes later to adjust doses if needed.
Can I drink alcohol before this test?
No, avoid alcohol before the test, as it may interfere with lab results or increase side effects from rifampin.
What if my results are outside the normal range?
If levels are too low, your doctor may increase your dose. If levels are too high, they may adjust your medication or monitor you more closely for side effects.
  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