If you are searching for M22-A3 for active laboratory compliance, be aware that standards are updated periodically.
Always verify with your laboratory director which edition is currently enforced by your regulatory agencies before implementing protocols based on an older PDF.
Summary: While a free PDF link is unavailable due to copyright protections, the document is essential for laboratory compliance. Professionals are encouraged to access it through their institution's CLSI membership or purchase it directly from the CLSI website to ensure they have the most accurate and legally compliant version.
The CLSI M22-A3 standard, titled "Quality Control for Commercially Prepared Microbiological Culture Media," is a critical document for clinical microbiology laboratories. It provides guidelines for both manufacturers and users to ensure the reliability and performance of ready-to-use culture media. Overview of CLSI M22-A3
The CLSI M22-A3 standard is the third edition of the M22 series, replacing the previous M22-A2 version. Its primary goal is to establish quality assurance procedures that streamline laboratory operations while maintaining high diagnostic accuracy.
Exempt Media: A cornerstone of this standard is the identification of "exempt" media. These are commercially prepared media with a proven history of high reliability and low failure rates (cutoff
). Labs do not need to perform full in-house quality control (QC) on these media if the manufacturer provides documentation of compliance.
Non-Exempt Media: Certain media, particularly those for fastidious organisms or those with higher historical failure rates, remain "non-exempt" and require full QC testing by the user before being released for patient testing. Key Responsibilities clsi m22a3 pdf link
The document clearly delineates the roles of different parties in the supply chain:
Manufacturers: Responsible for testing each lot for growth, selectivity, inhibition, and biochemical responses.
Distributors: Must ensure proper storage and handling during transit to maintain media integrity.
Users (Laboratories): Must document the receipt and physical condition of every shipment (e.g., checking for cracked plates, hemolysis, or contamination) and perform required QC for non-exempt media. Accessing the PDF
Because CLSI standards are copyrighted materials, they are typically not available for free download as a full PDF. You can obtain official copies through the following platforms:
CLSI Official Store: The primary source for the M22 document and its updates.
ANSI Webstore: Offers the CLSI M22-A3 PDF for purchase and provides a free preview of the table of contents and scope. If you are searching for M22-A3 for active
Standards Store: Retailers like Accuris also provide the document, often noting it as CLSI M22-A3 (R2018) to reflect its most recent reaffirmation. Implementation in Modern Labs
Historically, laboratories had to perform extensive quality control testing on every single batch of media they received from manufacturers. This was time-consuming and costly.
CLSI M22-A3 revolutionized this process by defining criteria for "User Quality Control." It outlines specific conditions under which a laboratory can rely on the manufacturer’s quality control testing rather than repeating it themselves. This concept is often referred to as "certificate of analysis" reliance.
Key aspects covered in the document include:
What it is: CLSI M22-A3 is the Clinical and Laboratory Standards Institute guideline titled "Methods for Antimicrobial Disk Susceptibility Testing of Bacteria Isolated from Animals" (3rd edition). It provides standardized procedures, interpretive criteria, quality control recommendations, and reporting guidance for disk diffusion antimicrobial susceptibility testing in veterinary microbiology.
Key features:
PDF link (official source): https://clsi.org/standards/products/microbiology/documents/m22/ Always verify with your laboratory director which edition
If you want, I can:
CLSI M22-A3, "Quality Control for Commercially Prepared Microbiological Culture Media," provides standards for classifying culture media into exempt and non-exempt categories based on reliability. While archived, it remains a key benchmark often used alongside IQCPs, available for purchase through technical standards retailers. Purchase the document at CLSI Shop.
The CLSI M22-A3 standard outlines quality control requirements for commercially prepared microbiological culture media, reducing the need for user testing on "proven reliability" media while establishing an acceptable failure rate of ≤0.5%. While applicable internationally, US laboratories now primarily follow Individualized Quality Control Plans (IQCP) under CLIA regulations rather than strictly adhering to M22-A3, which was updated to include 27 additional exempt media types. Purchase the document directly at
It is a common practice for laboratory professionals and students to search for a "CLSI M22-A3 PDF link" online. However, it is important to understand the copyright status of these documents.
The Official Source: CLSI documents are copyrighted intellectual property. They are not typically available for free legal download via public PDF links. To obtain a legitimate copy, you must visit the official CLSI website (clsi.org). They offer these standards for purchase as digital PDFs or print copies.
Institutional Access: If you work in a hospital or a university laboratory, you likely do not need to purchase the document individually. Most accredited institutions maintain a subscription to the CLSI library. You should check your laboratory’s policy and procedures manual or ask your laboratory director for access to the facility’s digital standards library.