What is the Cat Scratch Fever (Bartonella IgG + IgM) Test?

The Cat Scratch Fever (Bartonella IgG + IgM) test is a blood test that detects antibodies produced in response to infection with Bartonella henselae. This bacterium is commonly transmitted through scratches or bites from cats, particularly kittens.

IgM antibodies usually indicate recent or active infection, while IgG antibodies suggest past exposure or later-stage infection. Testing both antibody types helps determine the timing and likelihood of infection.

This test is commonly used when cat scratch disease is suspected based on symptoms, exposure history or unexplained lymph node enlargement.

Why do I need a test for Cat Scratch Fever (Bartonella IgG + IgM)?

You may need this test if you develop symptoms after contact with a cat or if you have unexplained swollen lymph nodes. While many cases are mild and self-limiting, Bartonella infection can cause prolonged symptoms and complications, especially in immunocompromised individuals.

Identifying the infection helps guide appropriate treatment and prevents unnecessary investigations for other causes.

Symptoms and scenarios where testing is recommended:

• Swollen or tender lymph nodes
• Fever or persistent fatigue
• History of cat scratch or bite
• Localised skin lesion at scratch site
• Headaches or malaise
• Unexplained lymphadenopathy
• Eye inflammation (neuroretinitis)
• Immunocompromised patient assessment

Benefits of the Cat Scratch Fever Test

• Identifies Bartonella infection
  Detects immune response to cat-transmitted bacteria.
• Differentiates recent and past infection
  IgM and IgG provide timing context.
• Supports diagnosis of lymph node swelling
  Helps explain unexplained lymphadenopathy.
• Guides appropriate antibiotic treatment
  Supports targeted therapy when required.
• Non-invasive blood-based testing
  No need for tissue biopsy initially.
• Useful in immunocompromised patients
  Where complications are more likely.
• Reduces unnecessary investigations
  Helps avoid invasive procedures.
• Clinically established infectious disease test
  Widely used in routine practice.

Step-by-Step: How Testing Works

Choose your preferred testing method

You can attend one of our UK partner clinics or arrange a home or hotel visit with a mobile phlebotomist.

Option 1 – In-Clinic Blood Draw

1. Select your nearest UK clinic and book an appointment.
2. A clinician or phlebotomist collects a venous blood sample.
3. The sample is analysed for Bartonella IgG and IgM antibodies.
4. Results are delivered securely online.

Option 2 – Home or Hotel Phlebotomy (+£60)

1. Book a UK-wide home or hotel visit at a convenient time.
2. A trained phlebotomist collects your blood sample on-site.
3. The sample is transported to the laboratory.
4. Results are uploaded digitally without the need to travel.

Your Results Explained

IgM Negative / IgG Negative

No evidence of Bartonella infection.
Early infection cannot be fully excluded if symptoms are recent.

IgM Positive (with or without IgG)

Suggests recent or active infection.
Clinical correlation and treatment may be required.

IgG Positive / IgM Negative

Indicates past exposure or resolving infection.
Usually reflects previous immune response.

Results should be interpreted alongside clinical symptoms and exposure history.