Determination of the infectious disease status of a sick newborn has been a major frustration for physicians who care for these patients. The physician must know whether or not the newborn has a significant infection, given symptoms and signs that can suggest infection or a myriad of noninfectious disorders. Simultaneously, the organism producing the infection must be identified, if possible. Pediatricians have relied on some "gold standards" in this regard: a blood culture, samples of cerebrospinal fluid, or other specimens from normally sterile body sites that yield direct evidence of the presence of pathogens. Furthermore, one wishes to identify and properly treat such new-borns as early in the course of the infection as is possible to avert death and minimize disability.
Physicians have relied on indirect means to select newborns who are most at risk of infection, as well as to predict which agent is likely to be responsible. Included