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Gentamicin Concentration (Serum/Plasma)

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

This test measures the amount of gentamicin, a type of antibiotic, in your blood. It helps doctors monitor how well your body is responding to treatment and whether the medication is at a safe level.

Quick summary

["Gentamicin levels help prevent dangerous side effects from too much antibiotic in your blood."]

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

Key facts at a glance

LOINC
73013-5
Short code
Gentamicin (neut) IgM SerPl Ql FC
Synonyms
Gentamicin (neut) IgM SerPl Ql FC
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
82784
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 taking gentamicin to treat serious bacterial infections, such as those in your blood, kidneys, or other parts of the body. Monitoring helps ensure the antibiotic works effectively while keeping your kidneys safe.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or vein to draw a blood sample. The process is quick and usually painless.

What the Test Results Mean

Results help your doctor decide if your dose of gentamicin needs adjustment. Too much can harm your kidneys, while too little may not fight infections properly. Your doctor will discuss findings with you.

Possible Side Effects or Risks

Gentamicin is generally safe when monitored properly. Rarely, it can cause kidney problems or hearing issues. Your doctor will watch for signs of these and adjust your treatment if needed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test is critical for patients on gentamicin therapy to balance antibiotic effectiveness with kidney protection. High levels may indicate overdose or poor kidney function, while low levels may mean the infection isn’t fully treated.

Short name

Gentamicin Level

Frequently asked questions

How often will I need this test?
Your doctor will schedule tests based on your treatment plan. Typically, levels are checked 30 minutes to 2 hours after your dose, then again later in the day to monitor how your body processes the drug.
What happens if my results are too high?
If levels are dangerously high, your doctor may reduce your dose, switch to a different antibiotic, or temporarily stop gentamicin to protect your kidneys. They’ll adjust your treatment plan accordingly.
Can I eat or drink before the test?
You can eat and drink normally unless your doctor specifies otherwise. This test only requires a blood sample, so no fasting is needed.
  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