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2023 Breakpoint Implementation Toolkit (2023 BIT)


Effective January 2024, clinical laboratories performing antimicrobial susceptibility testing (AST) will be required to use breakpoints currently recognized by Clinical and Laboratory Standards Institute (CLSI) or US Food and Drug Administration (FDA).

Together CLSI, Association of Public Health Laboratories (APHL), American Society for Microbiology (ASM), College of American Pathologists (CAP), and Centers for Disease Control and Prevention (CDC), have jointly developed this Breakpoint Implementation Toolkit (BIT) to assist clinical laboratories in updating minimal inhibitory concentration (MIC) breakpoints.

The kit is provided in a streamlined format and designed to guide performance of a verification or validation study required to update breakpoints. Also included are links to other resources that explain the rationale behind breakpoint updates, regulatory requirements for updating breakpoints, and detailed instructions for performing an AST breakpoint validation or verification. Manufacturers of AST systems can provide guidance on breakpoints used and clearance status with their systems.

Introduction: 2023 Breakpoint Implementation Toolkit

Includes how to use the 2023 Breakpoint Implementation Toolkit, definitions, references, and resources, and a Pathway for Updating Breakpoints (Figure 1).

Part A. Breakpoints in Use

Part A is provided to help laboratories meet the CAP requirement that laboratories should document all breakpoints in use in their laboratory.

Part B. CLSI vs FDA Breakpoints

Part B. includes a listing of all current CLSI breakpoints in M100-Ed33 with corresponding FDA breakpoints. This allows laboratories to identify whether their breakpoints, as identified in part A. of this toolkit, are current with CLSI and/or FDA breakpoints.

Part C. Breakpoint Implementation Summary

A template for documenting results of verification or validation studies to update breakpoints. This template can serve of evidence of support for your study for any accreditation or regulatory body.

Part D. CDC and FDA AR Bank BIT Isolate Sets

Includes CDC and FDA Antibiotic Resistance Isolate Bank isolate sets available for use in breakpoint verification and validation studies. Lists specific AR Bank Panels that are recommended for testing when using the BIT.

Part E. Instructions for Use of 2023 BIT Part F

Instructions for use on how to use part F, the prefilled Excel worksheet. It contains MIC results from the AR bank.

Part F. AR Bank Data Entry and Calculations

Part F. AR Bank Data Entry and Calculations (for earlier versions of MS Office/Excel that precede MS365)

Excel workbook prefilled with the AR Bank BIT set isolates and their results.


Part G. Blank Form for Data Entry

Template for validations or verifications using isolates other than those listed in the AR Bank BIT sets included in this toolkit.

Download Entire Toolkit