Fever is frequently observed in patients with hematological disorders, especially neutropenia. Their positive blood culture is usually low, and the condition is variousely termed. suspicious of sepsis, fever of unknown origin, etc. Although many such patients respond well to antibacterial or antifungal agents, suggesting infection, they are excluded from the clinical studies of antibiotics due to the lack of documented infection evidence. Given the rapid progression of the symptoms and their high mortality the diagnosis of febrile neutropenia (FN) is proposed. FN is now approved in 56 countries as an indicative diagnosis of antibiotics. Because of unknown etiology, guidelines for its empirical treatment were reported by the infectious Disease Society of America (IDSA) and frequently revised up to 2002. We started an FN study in Japan and published Japanese guidelines in 1998. We have also conducted a confirmatory study. This article reviews the difference in American and Japanese guidelines and their prejected revison.
