This manual presents laboratory procedures for the differentiation and identification of disease agents from clinical materials. Included are procedures for the collection of specimens, preparation of culture media, pure culture methods, cultivation of the microorganisms in natural and simulated natural environments, and procedures in identification. Also included are sensitivity determinations, safety practices in the clinical laboratory, and clinical laboratory monitoring of nosocomial diseases. For the more frequently performed tests, the principle of the test, the reagents and equipment needed, the preliminary steps, complete procedures, and interpretation of results are included. (Author/CS)