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CLSI Publishes New and Updated Interference Testing Documents

Published by the Clinical and Laboratory Standards Institute

Wayne, Pennsylvania, USAThe Clinical and Laboratory Standards Institute has published two clinical interference testing documents: Interference Testing in Clinical Chemistry, 3rd Edition (EP07-Ed3) and Supplemental Tables for Interference Testing in Clinical Chemistry, 1stEdition (EP37-Ed1). EP07 provides background information, guidance, and experimental procedures for investigating, identifying, and characterizing the effects of interferents on clinical chemistry test results. EP37 includes recommended testing concentrations for analytes and endogenous substances that may interfere in clinical chemistry measurement procedures and is intended for use with the evaluation procedures in EP07.

Robert J. McEnroe, PhD, Chairholder of the Document Development Committee on Interference Testing in Clinical Chemistry, said, “Team members from multiple disciplines worked together to significantly improve, clarify and standardize the process for interference testing. The new edition of EP07 enables the reader to carefully assess the source, direction, and magnitude of error in medical laboratory measurements. Whether you are a manufacturer of in vitro diagnostic measuring systems or a clinician responsible for ensuring that a measurement procedure is robust and specific enough to meet specific clinical requirements, these documents provide clear and concise guidance.”

  • EP07 provides guidance on:
    • How to perform and evaluate interference testing.
    • Step by step guidance in preparing for interference testing.
    • Data reduction methods and representation of results.
  • EP37 provides guidance on:
    • Recommended metabolite and drug test concentration levels
    • Testing families of drugs or understanding the underlying cause of the interference based on chemical structure, which is provided when possible.  
    • Unit conversion, which is an often-cited cause for error. Examples are provided.

For more information about EP07 and EP37, contact Patrick McGinn at pmcginn@clsi.orgor +1.484.588.5933.

CLSI sets the standard for quality in medical laboratory testing. A not-for-profit membership organization, CLSI brings together the global laboratory community for the advancement of a common cause: to foster excellence in laboratory medicine.

For nearly 50 years, our members, volunteers, and customers have made CLSI a respected, transformative leader in the development and implementation of medical laboratory testing standards. Through our unified efforts, we will continue to set and uphold the standards that drive quality test results, enhance patient care delivery, and improve health care around the world.

By using CLSI standards, laboratorians can improve process quality, speed the development of standard operating procedures, and implement safer practices with greater ease and efficiency.