It explicitly defines the roles of the manufacturer, distributor, and end-user laboratory.
M22-A3 introduced several significant changes from the previous M22-A2 version based on extensive surveys by the :
The acceptable failure rate cutoff for exempting media was increased from 0.3% to 0.5% . clsi m22a3 pdf
Excessive moisture, dehydration, or frozen/melted agar. Contamination: Any visible growth or excessive bubbles. Purchasing and Access
It applies to all commercial media regardless of packaging, such as plates, tubes, or bottles. Major Updates in the Third Edition (A3) It explicitly defines the roles of the manufacturer,
The standard, titled "Quality Control for Commercially Prepared Microbiological Culture Media; Approved Standard—Third Edition," provides a framework for both manufacturers and laboratory users to ensure the reliability of ready-to-use culture media. Published in 2004, it serves as a consensus-based guide for maintaining quality assurance in clinical microbiology. Key Purpose and Scope
The primary premise of M22-A3 is to reduce the burden of redundant testing. It identifies specific media of "proven reliability" for which users do not need to perform additional retesting if the manufacturer's quality control (QC) practices meet established criteria. Contamination: Any visible growth or excessive bubbles
Quality Control for Commercially Prepared Microbiological Culture Media
Use the standard to establish rigorous QC protocols for every lot.