Bartonella henselae Ab

What is Bartonella henselae Ab?

Measures antibodies against Bartonella henselae, the bacterium responsible for cat scratch disease, reflecting past or recent exposure.

This test detects IgG and/or IgM antibodies against Bartonella henselae, a bacterium usually transmitted through cat scratches, bites, or flea exposure and best known for causing cat scratch disease. It relates to the immune system and, in some presentations, to lymph node health, since swollen lymph nodes are a hallmark feature. Clinicians commonly order it when there is a history of cat contact together with unexplained lymph node swelling, prolonged low-grade fever, or fatigue. Because antibody testing can show cross-reactivity with other Bartonella species and results can remain positive long after exposure, this test is interpreted alongside history, physical findings, and sometimes additional laboratory methods.

Tests often checked alongside this

• Bartonella quintana Ab — a related species tested when exposure history is unclear
• Complete Blood Count (CBC) — general marker of immune and inflammatory activity
• Erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) — general inflammation markers sometimes checked alongside

How this can show up in how you look and feel

• May be associated with tender, swollen lymph nodes near a scratch or bite site
• May be associated with low-grade fever or fatigue
• May be associated with a small bump or blister at the site of a cat scratch

What can affect this marker

• Timing of exposure relative to testing
• Immune status
• Possible cross-reactivity with other Bartonella species
• Lab-to-lab variability in assay methods

What to track over time

• Whether antibody levels change on repeat testing
• How results relate to lymph node swelling or other symptoms over time
• Whether imaging or additional testing of affected lymph nodes is being considered

What to ask your doctor

• Does my exposure history to cats fit with this result?
• Could my swollen lymph nodes have another cause?
• Is any additional testing needed to confirm this exposure?
• Should this be interpreted alongside my recent symptoms?

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