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Gentamicin Antibiotic Susceptibility Test (Genotypic)

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

This test analyzes genetic information to determine how your body may respond to the antibiotic gentamicin, helping healthcare providers tailor treatment for infections.

Quick summary

["Genotypic testing helps identify potential resistance before starting antibiotic therapy."]

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

Key facts at a glance

LOINC
89481-6
Short code
Gentamicin Islt Genotyp
Synonyms
Gentamicin Islt Genotyp
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
genotyping
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 recommend this test if you have a suspected infection that could be resistant to gentamicin, or if you’re at higher risk for antibiotic-resistant bacteria. It helps avoid unnecessary antibiotics or adjust treatment plans more precisely.

What Does the Test Measure?

Instead of measuring gentamicin levels in your blood (like traditional testing), this test examines your DNA to check for genetic markers that might indicate resistance to gentamicin. This approach helps predict how your body will react to the drug.

How Is the Sample Collected?

A blood sample is typically taken from a vein in your arm. The sample is then sent to a lab for genetic analysis to identify specific genetic sequences related to gentamicin resistance.

What Are the Next Steps?

Results will guide your doctor in deciding whether to use gentamicin, adjust the dose, or choose an alternative antibiotic. Follow-up may include additional testing or monitoring based on the outcome.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Gentamicin Genotyping

Frequently asked questions

What does a positive result mean?
A positive result indicates the presence of genetic markers that may suggest gentamicin resistance. This doesn’t confirm the infection is resistant yet—your doctor will consider clinical findings and may order additional tests to confirm treatment planning.
How long does it take to get results?
Results are typically available within 1–2 weeks, depending on lab processing times. Your doctor will contact you once results are ready.
Is this test covered by insurance?
Coverage depends on your insurance plan and clinical indication. Check with your provider or insurance company to confirm if this specialized testing is covered under your plan.
  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