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Gentamicin Serum Concentration (Mass Concentration)

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

This test measures the amount of gentamicin, an antibiotic, in your blood serum. It helps doctors monitor how well your body is responding to treatment and adjust doses if needed.

Quick summary

["Gentamicin levels help prevent dangerous side effects from antibiotic overuse."]

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

Key facts at a glance

LOINC
267-5
Short code
Gentamicin Islt MIC
Synonyms
Gentamicin Islt MIC
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
mic
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 Is This Test Done?

Your doctor may order this test if you’re receiving gentamicin therapy, particularly for serious infections like sepsis or severe bacterial pneumonia. It helps ensure the antibiotic is at an effective level without causing harm to your kidneys or nerves.

What to Expect Before the Test

No special preparation is needed. A blood sample is drawn from a vein, usually in your arm, by a healthcare professional. The process takes a few minutes, and you may feel slight discomfort.

What the Results Mean

Results are used to guide treatment decisions. Low levels may indicate the antibiotic isn’t working well, while dangerously high levels could require dose adjustments or temporary stopping of the medication.

Common Reasons for Testing

Doctors often check gentamicin levels if you have kidney problems, hearing issues, or if you’re receiving high doses of the antibiotic for extended periods.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Monitoring Toxicity and Effectiveness

Short name

Gentamicin Level (Serum)

Frequently asked questions

Why is this test important for my health?
This test helps balance the need for effective infection control with the risk of antibiotic-related side effects. High levels can damage your kidneys or nerves, while insufficient levels may fail to treat your infection. Your doctor will use these results to adjust your treatment plan.
How often will I need this test?
The frequency depends on your treatment plan. Some patients may need levels checked daily or every few days during initial therapy, then less often as your doctor determines stability.
What if my results are outside the expected range?
If your results are unusually high, your doctor may reduce or temporarily stop the antibiotic. If levels are too low, they may increase your dose or switch to a different antibiotic. Always follow your healthcare provider’s instructions.
  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