scope:

This guideline provides a protocol for assessing equivalence or suitability for use of a different specimen type compared with the established primary specimen type for a medical laboratory measurement procedure or qualitative examination. This guideline provides a general framework for studies that establish equivalence among similar-matrix specimen types and clinical suitability among dissimilar-matrix specimen types. It also includes instructions for laboratory verification of alternate specimen types for commercial measurement procedures. This guideline applies to both quantitative measurement procedures and qualitative examinations. The intended users of this guideline are manufacturers, developers of medical laboratory measurement procedures, and laboratorians verifying alternate specimen types.

EP35 is intended to be used for specimen types for which the desired measurand has a known clinical indication and for which adequate clinical information is available to establish risk-based clinical performance goals. Establishing clinically based performance goals is beyond this guideline's scope.

EP35 focuses on the effect of specimen type on the analytical measurement procedure. There may also be preexamination factors between specimen types that can affect results. These differences may require additional studies to characterize their effect on the results. Such preexamination factors are outside of the scope of EP35.