CLSI EP39 Plus
A Hierarchical Approach to Selecting Surrogate Samples for the Evaluation of In Vitro Medical Laboratory Tests
This guideline defines what a surrogate sample is, offers recommendations for when to use surrogate samples, and outlines a process for selecting the most appropriate surrogate samples.
This document includes a copy of the CLSI EP39 Guide to help laboratories and manufacturers apply the concepts and study designs presented in CLSI EP39, including the selection and evaluation of surrogate samples, in a practical, step-by-step format. This guide cannot be purchased separately and is available in electronic format only. CLSI EP39 Guide was published 17 March 2026.
This reaffirmed document has been reviewed and confirmed as suitable to remain published without revision to content, as of October 2025.
{{FormatPrice(currentPrice)}}
Free
{{FormatPrice(nonMemberPrice)}} List PriceClinical and Laboratory Standards Institute guideline EP39—A Hierarchical Approach to Selecting Surrogate Samples for the Evaluation of In Vitro Medical Laboratory Tests establishes a standard definition of a surrogate sample. It presents a hierarchical approach for determining when to use surrogate samples and selecting an appropriate one. It also describes elements of a surrogate sample plan and includes technical preparation guidance for the characteristic to be measured or detected and for artificial matrix compositions. This guideline provides examples for specific performance study types.
This guideline establishes a definition of "surrogate sample" and an approach for selecting, preparing, and using these samples. It discusses surrogate sample:
• Composition
• Technical preparation
• Selection criteria
• Documentation and planning
• Use in specific performance study types
The intended users of this guideline are in vitro diagnostic (IVD) device developers, laboratorians, and regulators. This guideline does not describe performance study design, which is covered in other standards and guidelines (see CLSI document EP19).
Clinical and Laboratory Standards Institute guideline EP39—A Hierarchical Approach to Selecting Surrogate Samples for the Evaluation of In Vitro Medical Laboratory Tests establishes a standard definition of a surrogate sample. It presents a hierarchical approach for determining when to use surrogate samples and selecting an appropriate one. It also describes elements of a surrogate sample plan and includes technical preparation guidance for the characteristic to be measured or detected and for artificial matrix compositions. This guideline provides examples for specific performance study types.
This guideline establishes a definition of "surrogate sample" and an approach for selecting, preparing, and using these samples. It discusses surrogate sample:
• Composition
• Technical preparation
• Selection criteria
• Documentation and planning
• Use in specific performance study types
The intended users of this guideline are in vitro diagnostic (IVD) device developers, laboratorians, and regulators. This guideline does not describe performance study design, which is covered in other standards and guidelines (see CLSI document EP19).