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Microbiological culture and susceptibility testing for *Escherichia coli* from urine specimen

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

This test helps identify if a urinary infection is caused by *E. coli* and determines which antibiotics may work best to treat it.

Quick summary

["It’s used to guide antibiotic choices for urinary infections suspected to be caused by bacteria."]

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

Key facts at a glance

LOINC
63480-8
Short code
P aerug.MRI Spec Ql Cult
Synonyms
P aerug.MRI Spec Ql Cult
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
organism-specific-culture
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

What This Test Measures

This test checks for the presence of *Escherichia coli* (a common urinary tract infection, or UTI, bacterium) in your urine. It also examines how different antibiotics might affect these bacteria, helping your healthcare provider choose the most effective treatment.

Why It’s Ordered

Your doctor may order this test if you have symptoms like frequent urination, pain, or fever that suggest a UTI. It’s particularly useful when other tests (like a urine culture without susceptibility) are needed to confirm the infection’s cause or if you’re allergic to certain antibiotics.

How the Test Works

A sample of your urine is collected and placed on a special growth medium. Bacteria, if present, grow into colonies over 24–48 hours. Then, small disks with different antibiotics are applied to see which ones stop bacterial growth, indicating effectiveness.

Preparation and Sample Collection

No special preparation is needed, but you may be asked to collect a midstream clean-catch urine sample to ensure the sample is clean and representative. Avoid using antibacterial soaps or douches before testing.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urinary *E. coli* culture and antibiotic sensitivity

Frequently asked questions

How long does it take to get results?
Results typically take 2–5 days, depending on lab processing times. Some labs may offer preliminary findings sooner, but final susceptibility data can take longer.
What if I have no symptoms but the test is positive?
A positive culture without symptoms may indicate an asymptomatic bacteriuria (ABU), which is usually not treated unless it’s associated with pregnancy, a urinary procedure, or other health risks. Your doctor will discuss this with you.
Can I take antibiotics before the test?
No, antibiotics before testing can interfere with results. If you’ve already taken antibiotics, inform your doctor immediately, as this may affect the accuracy of the culture and susceptibility findings.
  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