Skip to content

Tobramycin trough concentration (serum/plasma)

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

This test measures the amount of the antibiotic tobramycin in your blood to help doctors monitor your dose and avoid potential side effects.

Quick summary

["Tobramycin levels help ensure safe and effective antibiotic treatment for infections like pneumonia or urinary tract infections."]

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

Key facts at a glance

LOINC
22752-0
Short code
Tobramycin Trough SerPl-sCnc
Synonyms
Tobramycin Trough SerPl-sCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Matters

Tobramycin is a strong antibiotic used to treat serious bacterial infections. Measuring its concentration in your blood helps doctors adjust your treatment to prevent too much or too little drug from being in your system, reducing risks like kidney damage or antibiotic resistance.

What to Expect Before the Test

You’ll likely have a small needle inserted into your arm or vein for a blood draw. The test is quick and usually done while you’re sitting comfortably. No special preparation is needed, but inform your doctor about any medications or allergies before the test.

How the Results Are Used

Your results will be compared to a target range set by your doctor based on your weight, kidney function, and other health factors. Low levels may mean your dose isn’t working well, while high levels could indicate toxicity.

Common Reasons for This Test

Doctors may order this test if you’re taking tobramycin for infections like cystic fibrosis, hospital-acquired pneumonia, or other serious bacterial infections. It’s often done during treatment to check how your body is handling the drug.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Tobramycin Level (Peak-to-Trough Monitoring)

Frequently asked questions

What does a high tobramycin level mean?
High levels may signal toxicity, which can cause side effects like hearing loss, kidney problems, or nerve damage. Your doctor will adjust your dose or switch medications if levels are too high.
How often will I need this test?
The frequency depends on your treatment plan. Typically, trough levels are checked 30–60 minutes before the next dose, often weekly or monthly, depending on your condition and kidney function.
Can I eat or drink before this test?
You can eat and drink normally unless your doctor specifies otherwise. Avoiding food or fluids can sometimes affect blood test results, but this test 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