CLSI EP09c-2018

This guideline provides recommendations for designing an experiment and selecting methods to quantify systematic measurement error (bias or difference) between measurement procedures based on comparing patient samples. It provides both difference plot and regression procedures to determine the relationship between two measurement procedures either across their measuring intervals or at selected concentrations. Intended users of this guideline are manufacturers of in vitro diagnostic (IVD) reagents—which includes those who create laboratory-developed tests—as well as regulatory authorities and medical laboratory personnel.

This guideline is for use with measurement procedures that provide quantitative numerical results. This guideline is not intended for use with ordinal IVD examinations, commonly referred to as qualitative procedures (see CLSI document EP12¹). This guideline is not intended to provide information on evaluation of random error (see CLSI documents EP05² and EP15³) or to determine the total error inherent in a comparison of measurement procedures (see CLSI document EP21⁴). It is not intended to measure the variability of multiple replicates collected during the measurement of a sample, nor is it intended to measure the bias of individual measurements such as those resulting from sample interference (as covered in CLSI document EP07⁵).