Serum immunoglobulin G avidity test as a tool for improving diagnosis of cat scratch disease.

Cat scratch disease (CSD) is a common cause of subacute infectious regional lymphadenitis, caused by Bartonella henselae. Presently, detection of anti-B. henselae antibodies by immunofluorescence antibody assay or enzyme immunoassay (EIA) is the most widely used diagnostic test for CSD, but both are limited in establishing the timing of infection with B.