I am currently sending my (?) Cat scratch disease cases to Dr. Kyung-Whan Min in the Department of Pathology at the Deaconess Hospital in Oklahoma City, OK.  He uses a Warthin-Starry histochemical stain, as well as immunoperoxidase staining for the localization of Bartonella (formerly Rochalimaea) henselae (the main etiologic agent).  Several years ago I was sent a sample of an antibody to B. henselae to test by one of the antibody companies.  It worked well on formalin-fixed, paraffin-embedded tissue, but (unfortunately) it never made it to the commercial market.  Hopefully, other antibodies will appear soon.

R. Cartun