Antibiotic Concentration Peak Titration (Serum/Plasma)
This test measures the highest level of a prescribed antibiotic in your bloodstream shortly after you take your medication. It helps doctors determine if the dose is working effectively and if you need adjustments.
["This test ensures your antibiotic is at the right level to fight infection without causing side effects."]
Key facts at a glance
- LOINC
- 15337-9
- Short code
- Other Antibiotic Peak Titr SBT
- Synonyms
- Other Antibiotic Peak Titr SBT
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- sbt
- 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
Doctors order this test when treating infections with antibiotics, especially in cases where the infection is resistant to standard doses or when monitoring long-term therapy. It helps prevent antibiotic resistance and ensures you receive the most effective treatment.
What to Expect Before the Test
No special preparation is needed. You may have a small needle inserted into your arm or vein to draw blood. If you’re on a long-term antibiotic regimen, your doctor may schedule this test during a routine clinic visit or after a few doses.
How the Test Works
A sample of your blood (serum or plasma) is collected and analyzed using a sensitive laboratory method to measure the antibiotic concentration. The test identifies the peak level shortly after you take your medication, typically within 1–2 hours.
What the Results Mean
Results show the antibiotic’s highest concentration in your blood. If the level is too low, your infection may not be fully treated. If it’s too high, you could experience side effects. Your doctor will compare these results to your prescribed dose and adjust treatment as needed.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is critical for personalized antibiotic therapy. It helps prevent underdosing (which may fail to cure the infection) or overdosing (which can harm your kidneys, liver, or other organs). For infections like tuberculosis, bacterial endocarditis, or severe sepsis, peak levels guide dosing to optimize safety and efficacy.
Short name
Peak Antibiotic Level
Frequently asked questions
How soon after taking my antibiotic should I have this test?
What if my results show a low antibiotic level?
Can I eat or drink before the blood draw for this 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