What is the Yersinia Antibodies test?

The Yersinia Antibodies test is a blood test that detects antibodies produced by the immune system in response to infection with Yersinia species, most commonly Yersinia enterocolitica and Yersinia pseudotuberculosis. These bacteria are typically acquired through contaminated food, especially undercooked pork, unpasteurised milk, or contaminated water.

The test usually measures IgG and/or IgA antibodies, which indicate previous exposure or recent infection. Unlike stool tests that detect active bacteria, antibody testing is particularly useful when symptoms are ongoing or delayed and the bacteria are no longer detectable in stool.

Clinically, this test is used in the investigation of chronic or recurrent gastrointestinal symptoms and post-infectious complications.

Why do I need a Yersinia Antibodies test?

Yersinia infection can cause acute gastroenteritis, but in some individuals symptoms persist or complications develop after the initial illness has resolved. Because stool tests may be negative by this stage, antibody testing helps confirm prior infection.

The test is especially relevant when gastrointestinal symptoms are followed by joint pain, inflammation, or autoimmune-like features. Identifying previous Yersinia exposure can guide further medical evaluation and management.

You may benefit from this test if you experience:

• Persistent or recurrent diarrhoea
• Abdominal pain or cramping
• Symptoms mimicking appendicitis
• Reactive arthritis or joint pain after gut infection
• Unexplained inflammation
• History of foodborne illness
• Ongoing symptoms with negative stool cultures

Benefits of the Yersinia Antibodies test

1. Identifies past Yersinia infection
   Useful when stool tests are no longer positive.
2. Supports investigation of chronic gut symptoms
   Helps explain ongoing digestive complaints.
3. Relevant for reactive arthritis assessment
   Yersinia is a known trigger for post-infectious arthritis.
4. Simple blood test
   No stool sample required.
5. Supports differential diagnosis
   Helps distinguish infectious from non-infectious causes.
6. Useful in delayed presentations
   Detects immune response weeks to months after infection.
7. Guides further clinical investigation
   Supports referral or additional autoimmune testing if needed.
8. Improves diagnostic clarity
   Adds objective evidence when history is unclear.

Step-by-step – How we offer this test

Option 1: Clinic-based blood test (UK-wide)

• Choose your nearest UK clinic
• Attend your appointment
• A clinician draws a blood sample
• Sample sent for antibody analysis

Option 2: Home or hotel visit (+£60, UK-wide)

• A qualified phlebotomist visits your location
• Blood sample taken at home or in your hotel
• No travel required
• Identical laboratory processing and reporting

Your results explained

Negative Yersinia antibody levels

Negative results suggest no evidence of previous Yersinia infection or testing performed too early for antibodies to develop.

Typical UK interpretation (negative):

• Below laboratory reference range

If suspicion remains high, repeat testing or alternative investigations may be advised.

Positive Yersinia antibody levels

Positive antibodies indicate previous exposure or recent infection with Yersinia bacteria.

Typical UK interpretation (positive):

• Above laboratory reference range

Results should be interpreted alongside symptoms and clinical history.

High antibody levels

High antibody titres may suggest recent or more significant immune response, particularly if symptoms are ongoing.

Typical UK interpretation (high):

• Significantly above reference range

Further clinical evaluation may be required.