CLSI Publishes EP34—Establishing and Verifying an Extended Measuring Interval Through Specimen Dilution and Spiking

Wayne, Pennsylvania, USA—The Clinical and Laboratory Standards Institute announces the publication of EP34—Establishing and Verifying an Extended Measuring Interval Through Specimen Dilution and Spiking, 1st ed. EP34 provides recommendations for establishing a dilution scheme to be used for patient specimens that contain measurand concentrations in the extended measuring interval above a measurement procedure’s upper limit of quantitation.

Guidance is provided on determining, validating, and verifying the appropriate diluent and dilution ratio to be used for such specimens. This guideline also covers creating spiked samples for use during dilution recovery studies and using spiking to determine the suitability of a sample matrix for dilution recovery studies. The intended users of this guideline are manufacturers of in vitro diagnostic tests and medical laboratory scientists, directors, and pathologists.

Jeffrey R. Budd, PhD, Chairholder of EP34 said, "It is often a medical necessity for laboratories to accommodate patients whose assay results are higher than the typical (analytical) measuring interval of that assay. EP34 describes methods for creating an extended measuring interval within which such results can be accurately measured. These reproducible methods for diluting and spiking patient specimens are used to establish, validate and verify this newly extended measuring interval."

Guidance is provided on:

• Determining the appropriate diluent and dilution ratio for specimens.
• Creating spiked samples for dilution recovery studies.
• Using spiking studies to determine the suitability of a specimen type for dilution recovery studies.

For more information about EP34, visit https://clsi.org/standards/products/method-evaluation/documents/ep34/ or contact Patrick McGinn at pmcginn@clsi.org or +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 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.

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