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Serum Gentamicin Concentration

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of gentamicin, a medication used to treat serious bacterial infections, in your blood serum. It helps doctors monitor your drug levels to ensure safe and effective treatment.

Quick summary

["This test helps prevent dangerous drug levels that could harm your kidneys or nerves."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
35668-3
Short code
Gentamicin SerPl-mCnc
Synonyms
Gentamicin SerPl-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0
Ref high
17
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 Is This Test Done?

Your healthcare provider may order this test if you’re taking gentamicin for an infection, especially if you have kidney problems or are receiving high doses. It helps track how well your body is processing the medication to avoid side effects like hearing loss or kidney damage.

What Does the Test Involve?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it’s analyzed to measure gentamicin levels. No special preparation is needed, but let your provider know if you’re taking other medications.

What Are Common Results?

Results are typically reported in micrograms per milliliter (mcg/mL). Your provider will interpret the results based on your specific medical needs, such as your weight, kidney function, and the dose of gentamicin you’re receiving.

How Often Is This Test Done?

The frequency depends on your treatment plan. For example, you might need blood tests every few days while taking gentamicin to check levels, especially if you’re receiving high doses or have kidney issues.

Reference range

NCBI: NSE 0-17 ng/mLN/A

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Gentamicin Level

Frequently asked questions

How long does it take to get results from this test?
Results are usually available within 24 to 48 hours, depending on your lab’s processing time. Your healthcare provider will contact you once they have the results.
What happens if my gentamicin level is too high?
If your level is too high, your provider may adjust your medication dose, slow down your infusion, or temporarily stop the drug to prevent damage to your kidneys or nerves. They’ll monitor you closely until levels return to a safe range.
Can I eat or drink before this test?
You can eat and drink normally before the test unless your provider gives specific instructions. No fasting is required for this blood test.
  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 17, 2026. · Read our editorial policy