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Antibody Detection by Line Blot (e.g., for *E. coli* O157:H7, Salmonella, or other pathogens via qualitative immunoassay)

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

This test detects antibodies in your blood that may indicate past or current exposure to certain harmful bacteria, such as those causing food poisoning or infections.

Quick summary

["Helps identify possible exposure to foodborne pathogens through antibody detection."]

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

Key facts at a glance

LOINC
89531-8
Short code
ENA SM Ab CSF Ql Line blot
Synonyms
ENA SM Ab CSF Ql Line blot
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
line-blot
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

What This Test Measures

The test uses a line blot method to identify specific antibodies against targeted bacteria. If antibodies are present, they bind to unique markers on the test strip, creating visible lines that confirm exposure. This is a qualitative test, meaning it only shows whether antibodies are present or not, not the exact amount.

How the Test Works

A small blood sample is drawn and processed to detect antibodies. The sample is applied to a membrane with immobilized bacterial antigens. If antibodies are present, they react with these antigens, forming a visible line on the test strip. This reaction indicates exposure to the bacteria.

Why It Might Be Ordered

Your healthcare provider may order this test if you’ve experienced symptoms like diarrhea, vomiting, fever, or abdominal pain after eating contaminated food, or if you’ve been exposed to a known foodborne pathogen.

Common Symptoms Linked to This Test

Symptoms such as diarrhea, nausea, vomiting, stomach cramps, fever, or dehydration may suggest exposure to bacteria detected by this test. However, symptoms can vary widely and may not always appear immediately.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Pathogen Antibody Screen (Line Blot)

Frequently asked questions

What does a positive result mean?
A positive result suggests your body has detected antibodies against specific bacteria, indicating past exposure. This does not always mean an active infection is present today, but it can help confirm exposure history or guide further investigation if symptoms persist.
What does a negative result mean?
A negative result means no detectable antibodies were found against the tested bacteria, suggesting either no exposure or that the exposure occurred before your body developed detectable antibodies (e.g., very recent or mild exposure).
How soon after exposure might I get results?
Results may take 24 to 48 hours, depending on lab processing times. Antibodies typically develop within days to weeks after exposure, so results may not reflect immediate infection but rather past exposure.
  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