Skip to content

Escherichia coli O157:H7 stool probe (qualitative detection)

Published: August 9, 2026Updated: August 17, 2026

This test checks for the presence of *Escherichia coli* O157:H7 bacteria in your stool. It helps identify a rare but serious foodborne illness that can cause severe stomach cramps, bloody diarrhea, and kidney failure in some cases.

Quick summary

["A positive result may indicate exposure to contaminated food or water, requiring medical attention and possible treatment."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
80682-8
Short code
E histolytica 18S rRNA Stl Ql NAA+probe
Synonyms
E histolytica 18S rRNA Stl Ql NAA+probe
Category
chemistry
Sample
stool
Container
Clean container
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
CPT
84484
SNOMED
302774002
Specimen volume
5 g
Stability
Refrigerated: 24h, Frozen: 7d
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your doctor may order this test if you experience symptoms like severe diarrhea with blood, abdominal pain, vomiting, or fever—especially if you’ve eaten undercooked meat, unpasteurized dairy, or contaminated produce. It’s also used in outbreaks or after travel to high-risk areas.

What to Expect Before the Test

No special preparation is needed. Bring any stool sample collected at home (if instructed) or visit a lab with a fresh sample. Wear old clothes—some labs use gloves or disposable gowns.

What Happens During the Test

A lab technician examines a small sample of your stool under a microscope or uses a specialized probe to detect the *E. coli* O157:H7 bacteria. Results are typically available within hours.

What the Results Mean

A **positive result** means the bacteria were found. A **negative result** means they were not detected in this sample, but you may still need further testing or monitoring if symptoms persist.

Reference range

Adult: 10-40 U/LN/A

Specimen: stool

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

E. coli O157:H7 stool test

Frequently asked questions

What are the possible symptoms or complications of E. coli O157:H7 infection?
Symptoms can range from mild diarrhea to life-threatening complications like hemolytic uremic syndrome (HUS), which damages kidneys. Seek emergency care if you develop severe pain, confusion, or difficulty urinating.
How long does it take to recover from this infection?
Recovery time varies but often takes 1–2 weeks. Antibiotics are rarely used unless severe symptoms occur. Rest, hydration, and avoiding dairy products may help.
Can I still spread the infection if my test is negative?
Yes, you may still be contagious even if the test is negative. Follow your doctor’s advice on isolation (e.g., avoiding contact with others) until symptoms resolve and you’re no longer contagious.
  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 17, 2026. · Read our editorial policy