The polymerase chain reaction: amplifying our options.

The polymerase chain reaction (PCR) has had a major impact on our ability to detect infectious agents. However, the impact of PCR has not been uniform throughout the discipline of infectious disease but instead has been applied in various contexts, depending on the current level of diagnostic sophistication for a given disease. The application of PCR in four contexts is presented along with a discussion of the potential of this technique to elucidate the natural history of infectious disease and to serve as a tool for the molecular elucidation of acute and chronic illness.