Who gets the final call on breakpoints?

• A. CLSI
• B. EMA
• C. FDA
• D. WHO

Answer: (C)

Breakpoints are the interpretive criteria that tell us whether an organism is susceptible, intermediate, or resistant to a drug. These criteria are developed by scientific groups (for example CLSI in the US and EUCAST in Europe) using data on drug concentrations, bacterial MIC distributions, PK/PD considerations, and clinical outcomes. In the United States, the final authority to approve or confirm what breakpoints a marketed diagnostic test reports on its labeling rests with the FDA. The FDA reviews the data and authorizes the device labeling, including which breakpoints can be used. So while CLSI/EUCAST provide the scientifically grounded criteria, the FDA has the ultimate say for regulatory labeling and patient-safety purposes within the US. Other bodies like EMA or WHO provide guidance, but they do not have the regulatory final say for US-labeled diagnostics.