Initial evaluation of patients with febrile neutropenia includes a thorough history and physical examination; a complete blood cell count; measurement of serum creatinine, blood urea nitrogen, transaminases, and C-reactive protein; and culture of blood (samples from a peripheral vein and/or catheter). Chest radiography is indicated for patients with respiratory signs or symptoms. Signs and symptoms of inflammation may be minimal or absent. However, a search should be undertaken in the sites most commonly infected, including the periodontium, pharynx, lower esophagus, lung, perineum, eyes, and skin. Blood samples, including samples from catheter lumen(s), if present, and a peripheral vein, should be obtained for cultures for bacteria and fungi. Urine culture is indicated in the presence of signs or symptoms of urinary tract infection, a urinary catheter in place, or abnormal results of urinalysis. Fever is defined as a single axillary temperature measurement of > or =37.5 degrees C (oral temperature of > or =38.0 degrees C). Neutropenia is defined as a neutrophil count of <1000 cells/mm3.