Skip to content

Rifampicin Quantitative Drug Level (Serum)

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

This test measures the amount of rifampicin, a medication used to treat certain bacterial infections like tuberculosis or other infections caused by bacteria that are resistant to other drugs.

Quick summary

["Understanding your rifampicin levels helps your doctor monitor how well your body is handling the medication."]

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

Key facts at a glance

LOINC
20385-1
Short code
rifAMPin Islt SlowMyco
Synonyms
rifAMPin Islt SlowMyco
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
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 rifampicin to ensure the drug is working properly and to check for side effects. It’s often done during treatment to adjust your dosage if needed.

What to Expect Before the Test

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

How the Test Results Are Used

The results help your healthcare provider determine if your rifampicin levels are within the safe range. If levels are too low, your medication may not be working effectively. If levels are too high, you might experience side effects.

Possible Side Effects

Rifampicin can cause mild side effects like nausea, stomach upset, or a temporary red-orange color in urine or tears. More serious side effects, such as liver problems, are rare but require immediate attention.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Rifampin Level

Frequently asked questions

What does a low level of rifampicin mean?
A low level may indicate the medication isn’t being absorbed well or isn’t working as intended. Your doctor might adjust your dosage or consider alternative treatments.
What does a high level of rifampicin mean?
High levels can lead to side effects like liver damage or allergic reactions. Your doctor will monitor you closely and may change your treatment plan.
How often should I have this test?
Your doctor will determine the timing based on your treatment plan. Typically, tests are done during the early and middle stages of treatment to ensure safety and effectiveness.
  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