Rapid identification of bacteria and yeast: summary of a National Committee for Clinical Laboratory Standards proposed guideline.

Using colony morphology on selected agars, Gram-stain morphology, and a number of 1-step biochemical or enzymatic tests, skilled microbiologists can identify the species of the majority of isolates seen routinely in a clinical laboratory. These results are often available more quickly than and are as accurate as those derived from conventional methods. The National Committee for Clinical Laboratory Standards has produced a guideline that describes tests that can be used to identify a number of aerobic gram-negative rods and gram-positive cocci, a number of commonly isolated anaerobes, and 3 species of yeast. An overview of the organisms included in the guideline, the tests that identify them, and the situations in which rapid testing is appropriate is presented here.