Nonculture techniques using blood specimens for the diagnosis of infectious disease

Recent technological advances have increased the use of blood as a source for diagnosis of local and systemic infectious diseases. Traditionally, viable organisms may be cultured from the blood and others identified microscopically. The ability to detect microbial products by physicochemical, bioactivity, and antigenic techniques and the ability to detect specific immunoglobulin M (IgM) responses to infection improve our diagnostic capabilities but also present new problems in determining clinical relevance. The diagnostic use and reproducibility of new tests should be verified by comparative clinical field testing before implementation.