September 3, 2008

New CLSI Guideline Addresses Quality Control for Commercial Microbial Identification Systems

Microbial identification systems (MISs) are test systems that utilize multiple substrates and/or reagents to identify aerobic or anaerobic bacteria, yeasts, molds, or yeast-like algae grown from culture. MISs have become increasingly complex, which has resulted in the need for a greater number of quality control (QC) organisms to check positive and negative reactivity for all components. In 2005, the American Society for Microbiology (ASM), at the suggestion of the Clinical Laboratory Improvement Advisory Committee (CLIAC), conducted a microbiology laboratory survey to determine the QC failure rates of commercial MISs in a random selection of laboratories that perform bacterial and fungal identification from culture. The data showed a failure rate of less than 0.1% for all commercial MISs surveyed.

As a result, Clinical and Laboratory Standards Institute (CLSI) used its consensus process to develop Quality Control for Commercial Microbial Identification Systems; Approved Guideline (M50-A). This includes guidelines that may be followed when using an MIS of proven reliability to take a modified QC approach, rather than meeting requirements included in the Clinical Laboratory Improvement Amendments of 1988 regulations.

Nancy L. Anderson, MMSc, MT(ASCP), Chief, Laboratory Practice Standards Branch, Division of Laboratory Systems, National Center for Preparedness, Detection, and Control of Infectious Diseases, Coordinating Center for Infectious Diseases, Centers for Disease Control and Prevention (CDC) and Chairholder of the subcommittee that developed the document explains, "The QC requirements in the CLIA regulations state that a positive and negative control must be checked for every reagent or substrate on an MIS panel. As systems have developed and become more complex, this has resulted in a need for testing large numbers of organisms in order to check every reagent or substrate. In addition, there are now some MISs whose identification algorithms do not allow for total compliance with this QC requirement. Thus, in some cases, meeting the CLIA requirement is now impossible; whereas in other cases, it imposes financial and workflow burdens on microbiology laboratories and may be unnecessary for MISs of proven reliability produced by manufacturers that meet quality standards and regulations for control and distribution. Development of M50 provides a means for reducing resources spent on QC testing."

The document specifies the QC responsibilities of the manufacturer, distributor, and user, and identifies conditions under which an MIS with proven reliability can qualify for streamlined QC testing.

For additional information on CLSI or for further information regarding this release, visit our website at or call +610.688.0100.

CLSI, formerly NCCLS, is a global, nonprofit, membership-based organization dedicated to developing standards and guidelines for the health care and medical testing community. CLSI's unique consensus process facilitates the creation of standards and guidelines that are reliable, practical, and achievable for an effective quality system.