Infectious diseases manifested in the peripheral blood

Microscopic examination of peripheral blood smears is a primary diagnostic modality for only a few infectious agents. A variety of organisms, however, may produce manifestations in blood. These be specific or nonspecific but sufficiently suggestive to trigger a search for an infectious agent. With a reasonable level of vigilance and an understanding of the morphologic, clinical, and epidemiologic features of various disorders, laboratorians may provide early diagnosis of infectious states. Rapid diagnosis in turn leads to reductions in health care costs, morbidity, and mortality.