Ethambutol Serum Concentration (Quantitative)
This test measures the amount of ethambutol, a medication used to treat tuberculosis, in your blood serum. It helps your healthcare provider monitor your drug levels to ensure proper dosing and avoid potential side effects.
["Your ethambutol levels help balance effectiveness and safety during tuberculosis treatment."]
Key facts at a glance
- LOINC
- 25195-9
- Short code
- Ethambutol Islt Slgr Mcbct AB 10.0
- Synonyms
- Ethambutol Islt Slgr Mcbct AB 10.0
- 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 ethambutol to treat tuberculosis. It helps assess whether your dose is working well in your body and whether you need adjustments to prevent low blood levels (which could make the drug less effective) or high levels (which could cause vision problems).
What to Expect Before the Test
No special preparation is needed. You’ll provide a blood sample, usually drawn from a vein in your arm. The process is quick and typically painless.
What the Results Mean
Results are compared to a general reference range for ethambutol in serum. Low levels may indicate insufficient absorption or drug interactions, while very high levels could signal toxicity. Your doctor will interpret results in the context of your treatment plan.
Common Reasons for Monitoring
Doctors monitor ethambutol levels to prevent vision changes (like blurred or reduced vision) caused by high drug concentrations. It also ensures the medication remains effective against tuberculosis bacteria.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Ethambutol is a key antibiotic for tuberculosis treatment, but its effectiveness depends on maintaining safe blood levels. Low levels may lead to treatment failure, while high levels can damage your optic nerve, causing vision loss. Regular monitoring helps balance these risks.
Short name
Ethambutol Level
Frequently asked questions
Why might my doctor order this test if I’m already taking ethambutol?
What are the most common side effects of ethambutol, and how does this test help prevent them?
Can I eat or drink anything before this blood test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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