What is the Leptospirosis (Weil’s Disease) Antibodies (IgM) test?

The Leptospirosis IgM antibody test is a blood test that detects IgM antibodies produced in response to infection with Leptospira bacteria. IgM antibodies typically appear early in the course of infection, making this test useful for identifying recent or acute leptospirosis.

Leptospirosis is a zoonotic bacterial infection transmitted through contact with water, soil or surfaces contaminated with the urine of infected animals, particularly rodents. Severe infection is known as Weil’s disease, which can affect the liver, kidneys and other organs.

This test is commonly used in acute illness, especially when symptoms develop after environmental or occupational exposure.

Why do I need a Leptospirosis IgM test?

Leptospirosis can range from mild flu-like illness to severe, life-threatening disease. Early detection allows prompt antibiotic treatment and reduces complications.

You may need this test if you:

• Have fever, chills and muscle pain
• Experience jaundice or dark urine
• Have headache and eye redness
• Have kidney or liver abnormalities
• Were exposed to floodwater or contaminated freshwater
• Work with animals or in agriculture
• Have unexplained febrile illness after travel

Symptoms commonly associated with leptospirosis include:

• Sudden high fever
• Severe muscle pain (especially calves)
• Headache
• Red or irritated eyes
• Nausea and vomiting
• Jaundice (Weil’s disease)

Benefits of the Leptospirosis IgM test

• Detects recent infection
  IgM antibodies indicate acute disease.
• Supports early diagnosis
  Enables timely antibiotic treatment.
• Relevant for Weil’s disease assessment
  Identifies severe leptospirosis risk.
• Clinically recognised infectious marker
  Used in tropical and infectious medicine.
• Useful after environmental exposure
  Especially following floods or freshwater contact.
• Simple blood test
  No invasive sampling required.
• Guides further confirmatory testing
  Indicates need for PCR or paired serology.
• Supports public health investigations
  Relevant in outbreak or exposure settings.

Step by step – how the test works

You can access Leptospirosis IgM testing UK-wide through two options:

1. Clinic appointment
   Attend your nearest UK clinic where a healthcare professional will take your blood sample.
2. At-home or hotel visit (£60 extra)
   A qualified phlebotomist comes to your home or hotel for sample collection.

Your sample is analysed in an accredited UK laboratory, and results are delivered securely.

Your results explained

Negative Leptospira IgM

No evidence of recent leptospirosis infection.

Typical UK interpretation:

• Leptospira IgM: Negative

Positive Leptospira IgM

Suggests recent or active leptospirosis infection. Clinical follow-up is required.

Typical UK interpretation:

• Leptospira IgM: Positive

Borderline or early infection

Repeat testing or confirmatory PCR may be recommended if symptoms persist.

Results must be interpreted alongside symptoms and exposure history.