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Escherichia coli (E. coli) in Stool by Culture and Sensitivity (C&S) with Specific Antibiotic Susceptibility Testing (Qualitative)

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

This test checks for the presence of *Escherichia coli* bacteria in your stool, which can help identify infections caused by this common gut bacterium.

Quick summary

["A positive result may indicate a bacterial infection needing treatment, while a negative result suggests no active infection from this strain."]

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

Key facts at a glance

LOINC
13329-8
Short code
E coli LT Spec Ql
Synonyms
E coli LT Spec Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
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 This Test Matters

E. coli is a frequent cause of gastrointestinal infections, including diarrhea. This test helps doctors determine if your symptoms are due to a bacterial infection that may require antibiotics, rather than a viral or other cause.

What to Expect Before the Test

No special preparation is needed. You may eat and drink normally. If you’re taking antibiotics, let your doctor know—this may affect results.

What the Test Involves

A small stool sample is collected in a container. The lab then grows the bacteria in a controlled environment to identify *E. coli* and check how it responds to antibiotics.

What the Results Mean

A positive result means *E. coli* was found, which may require treatment with antibiotics. A negative result means no *E. coli* was detected, but other causes of symptoms could still exist.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: This test is critical for diagnosing bacterial gastrointestinal infections, guiding antibiotic use, and distinguishing infections from other causes like food poisoning or viral illnesses. Susceptibility testing helps ensure the right antibiotic is chosen to treat the infection effectively.

Short name

E. coli stool culture

Frequently asked questions

What does a positive result mean?
A positive result means *E. coli* was detected in your stool. This may indicate a bacterial infection that could cause symptoms like diarrhea, stomach pain, or fever. Your doctor will determine if antibiotics are needed based on the specific strain and your symptoms.
How long does it take to get results?
Results typically take 3–5 business days. If urgent, your doctor may request expedited testing. Follow-up may include additional tests or a repeat stool sample if needed.
Can I eat or drink before the test?
Yes, you can eat and drink normally. Avoiding special preparation helps ensure accurate results, but antibiotics or certain medications may affect the outcome—let your doctor know if you’re taking them.
  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