Diagnostic key to mycobacteria encountered in clinical laboratories.

A diagnostic key has been developed which will permit identification of most mycobacteria encountered in clinical laboratories. The key is based on performance of a few simple tests. The efficiency and accuracy of the key was evaluated in terms of correlation between identifications based on the few tests and those arrived at through application of the techniques of numerical taxonomy, which involves a large battery of tests. Of 679 cultures of mycobacteria other than Mycobacterium tuberculosis, 86.5% were correctly identified by use of the key, and only 1.8% of the cultures were erroneously identified. The remaining cultures required further examination.