Bartonella (Cat Scratch) IgM Antibody Test

The Bartonella (Cat Scratch) IgM Antibody Test is a blood test used to detect recent or acute infection with Bartonella bacteria, most commonly Bartonella henselae, the organism responsible for cat scratch disease. It is particularly useful for patients who have been scratched or bitten by a cat (or kitten) and who develop symptoms such as a swollen, tender lymph node near the site of injury, fever, fatigue, headache, or a papule or pustule at the scratch site. The test may also be requested when there is clinical suspicion of other Bartonella-associated conditions, including bacillary angiomatosis, peliosis hepatis, or culture-negative endocarditis, particularly in immunocompromised individuals.

The test works by measuring IgM antibodies, which are the first class of antibodies produced by the immune system during an acute infection. A positive IgM result generally indicates recent or current exposure to Bartonella, although it should always be interpreted alongside the patient's clinical history and other laboratory findings. This assay is typically performed using enzyme-linked immunosorbent assay (ELISA) or indirect immunofluorescence assay (IFA) methodology, both of which are well-established techniques for detecting Bartonella-specific antibodies in serum.

Biomarkers Included

• Bartonella (Cat Scratch) IgM Antibody

Why it matters

Cat scratch disease is usually self-limiting in healthy individuals, but it can cause significant morbidity in immunocompromised patients and may lead to disseminated infection if not recognised. Identifying an acute Bartonella infection through IgM antibody testing supports timely clinical assessment, appropriate management, and informed decisions about further investigation or treatment. It also helps differentiate Bartonella from other causes of lymphadenopathy and fever, guiding more targeted care.

• Bartonella (Cat Scratch) IgM Antibody

No special preparation required.

For blood tests, we recommend drinking plenty of water beforehand to ensure smooth sample collection. If you are taking any regular medication, continue to do so unless advised otherwise by your doctor.