The Gram Stain: The Century-Old Quintessential Rapid Diagnostic Test

Although described over 100 years ago, the Gram stain in the setting of the contemporary clinical microbiology laboratory still remains the prototype rapid test rivaling other modalities such as fluorescein-conjugated monoclonal antibodies and nucleic acid probes for diagnostic purposes. Often underused and abused and nearly abandoned as a diagnostic adjunct, this simple staining technique in the hands of an experienced viewer with an eye toward subtleties and the unexpected is without peer for the recognition of a multitude of infectious agents.