E. coli O157:H7 Antibody Screening Test (Serum/Plasma)
This test detects antibodies in your blood that may indicate past exposure to *Escherichia coli* (E. coli) strain O157:H7, a bacterium often linked to foodborne illnesses.
["Helps identify possible infection history without testing for the bacteria itself."]
Key facts at a glance
- LOINC
- 82204-9
- Short code
- E coli O157 DNA Stl Ql NAA+n-prb
- Synonyms
- E coli O157 DNA Stl Ql NAA+n-prb
- 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
- non-probe-amp-tar
- CPT
- 84484
- SNOMED
- 302774002
- Specimen volume
- 5 g
- Stability
- Refrigerated: 24h, Frozen: 7d
- TAT
- 4–24 hours
- Order
- routine
What This Test Measures
The test looks for antibodies produced by your immune system in response to exposure to *E. coli* O157:H7. Antibodies are proteins your body makes to fight infections. This screening is not a direct test for the bacteria but can help track immune response if you’ve been exposed.
Why It Might Be Ordered
Your healthcare provider may order this test if you’ve had symptoms like severe stomach cramps, bloody diarrhea, or if you’ve been exposed to contaminated food/water. It’s also used in outbreaks or research settings to monitor immune response.
Sample Collection and Preparation
A blood sample is drawn from your arm, and the serum or plasma is tested for antibodies. No special preparation is needed, but fasting may be advised depending on your provider’s instructions.
What to Expect After the Test
Results are typically ready within 1–3 business days. You’ll discuss them with your provider, who may recommend further testing (e.g., stool culture) if symptoms persist or exposure is suspected.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Positive results suggest your immune system has encountered *E. coli* O157:H7, but they don’t confirm active infection. This test is often used alongside other diagnostic tools (like stool cultures) to guide treatment or outbreak investigations. False positives can occur with prior exposure or cross-reactions, so results should be interpreted by a healthcare provider.
Short name
E. coli O157:H7 Antibody Screen
Frequently asked questions
Could this test show if I currently have an E. coli infection?
Why would my doctor order this test if I don’t have symptoms?
What does a positive result mean for my health?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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