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Escherichia coli Antigen (Urinary) – Qualitative

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

This test detects the presence of *Escherichia coli* bacteria in your urine, which can help identify urinary tract infections (UTIs).

Quick summary

["A positive result may signal a UTI needing treatment."]

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

Key facts at a glance

LOINC
45162-5
Short code
E coli O157 Ag Islt Ql LA
Synonyms
E coli O157 Ag Islt Ql LA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
la
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

The test looks for specific proteins (antigens) produced by *E. coli* bacteria in your urine. These proteins are unique to this type of bacteria, helping doctors confirm if it’s the cause of symptoms like frequent urination, pain, or cloudy urine.

Why It’s Done

Your healthcare provider may order this test if you have symptoms of a UTI, such as discomfort during urination, frequent urges to urinate, or unusual urine color/odor. It’s also used to monitor treatment effectiveness or check for recurrent infections.

Sample Collection and Testing

You’ll likely provide a midstream urine sample (clean-catch) or a sterile container sample. The lab tests a small portion of your urine using an immunoassay method to detect the bacterial antigen.

What the Results Mean

A **positive** result means *E. coli* was found in your urine, strongly suggesting a UTI. A **negative** result means no detectable bacteria were present, but other causes of symptoms (like kidney stones or vaginal infections) could still be possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

E. coli is the most common cause of UTIs in adults. Detecting it helps confirm the diagnosis, guide antibiotic selection, and prevent unnecessary tests. False negatives can occur if the infection is mild or not present in the urine sample, while false positives are rare with this test method.

Short name

E. coli Urine Test

Frequently asked questions

How long does it take to get results?
Results are typically available within 24 to 48 hours, depending on lab processing times. Your doctor will discuss the findings with you during your follow-up visit.
What if my test is positive?
If the test is positive, your doctor will likely prescribe antibiotics to treat the UTI. You may also need to drink extra fluids, avoid irritating products (like bubble baths), and follow any specific care instructions they provide.
Can I take anything to prepare for this test?
No special preparation is needed. Avoiding certain medications (like antibiotics) before testing may not be necessary unless your doctor advises it. If you’re pregnant or have a history of kidney issues, let your provider know before the 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 16, 2026. · Read our editorial policy