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E. coli O157:H7 DNA in Stool by Nucleic Acid Amplification Probe

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

This test checks for the presence of genetic material from *Escherichia coli* (E. coli) strain O157:H7 in your stool. It helps identify infections caused by this harmful bacteria.

Quick summary

["A simple test to detect a specific type of harmful bacteria that can cause severe illness."]

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

Key facts at a glance

LOINC
38990-8
Short code
E coli O157H7 DNA Spec Ql NAA+probe
Synonyms
E coli O157H7 DNA Spec Ql NAA+probe
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
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 O157:H7 is a rare but serious strain of bacteria that can lead to life-threatening conditions like hemolytic uremic syndrome (HUS) or kidney failure. Early detection is crucial for prompt treatment and preventing spread.

How the Test Works

This test uses a specialized probe to detect the DNA of E. coli O157:H7 in your stool sample. It’s highly sensitive and can identify even small amounts of the bacteria’s genetic material.

What to Expect Before the Test

No special preparation is needed. You’ll provide a stool sample (like a bowel movement) in a container provided by your healthcare provider. The test is quick and painless.

What to Expect After the Test

Results are typically ready within 24–48 hours. If the test is positive, your doctor will guide you on next steps, which may include antibiotics or additional monitoring.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

E. coli O157:H7 Stool Test

Frequently asked questions

This test is primarily used to diagnose E. coli O157:H7 infections in people who experience symptoms like severe stomach cramps, bloody diarrhea, or vomiting. It’s especially important for children, the elderly, or those with weakened immune systems.
This test helps confirm if you have an infection caused by E. coli O157:H7, which can lead to serious complications. Early identification allows for timely treatment to prevent complications like kidney failure.
How accurate is this test?
This test is highly accurate for detecting E. coli O157:H7 DNA in stool. However, it may not detect all cases where the bacteria are present, especially if the infection is very early or has already cleared. Follow-up testing may be needed if symptoms persist.
Can I eat or drink before the test?
No special diet or fasting is required. However, avoid eating or drinking anything that could interfere with the test results, such as certain supplements or medications. Stick to clear liquids if you’re instructed to do so before the procedure.
  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