Clinical and Laboratory Standards Institute document M56-A—Principles and Procedures for Detection of Anaerobes in Clinical Specimens; Approved Guideline provides procedures for performing testing and providing accurate, reliable, and useful results to laboratories with differing levels of expertise in anaerobe bacteriology. Preexamination requirements for specimen selection, collection, transport, timely processing, and examination procedures are discussed. Rapid and complex methods are compared for their ability to provide definitive identifications. Because the delivery of preliminary reports is vital to patient care when complex final reports are delayed, interpretations of direct smears and culture results are presented to help laboratorians confidently issue preliminary reports. Descriptions of anaerobes involved in human disease and a discussion of diagnostic methods for Clostridium difficile disease are presented. Guidelines for establishing competency testing to laboratories at their various levels of expertise and complexity are included. Because failures in good practices for preexamination, examination, and postexamination techniques can put patients at risk, a discussion of risk assessment during the design and implementation of anaerobe bacteriology protocols is included.

This document provides guidance for preexamination, examination, and postexamination procedures associated with the culture of anaerobic bacteria. Because anaerobic bacteria are part of human normal flora and are sensitive to oxygen exposure, good preexamination methods are essential. These recommendations include methods for collecting proper specimens from appropriate clinical sites and for transport procedures that protect anaerobes from oxygen exposure so that all pathogens involved in infections can be detected. The optimal methods needed to provide accurate, timely, and sufficient information for appropriate medical decisions are included, along with a discussion of the use and value of partial and full isolate IDs. Also included in this guideline are recommendations for interpreting results, assistance in understanding the value of rapid preliminary results, and guidance on issues of QC, QA, and competency. The intended audience includes medical technologists, infectious disease physicians, microbiology laboratory directors, pathologists, and researchers. Because anaerobe antimicrobial susceptibility testing (AST) methods are presented in CLSI documents M11 and M100, this document limits its discussion to the need and indications for AST.