Overview
EN ISO 20166-2:2018 - "Molecular in vitro diagnostic examinations - Specifications for pre‑examination processes for formalin‑fixed and paraffin‑embedded (FFPE) tissue - Part 2: Isolated proteins" provides standardized guidance for the pre‑examination phase of protein analysis from FFPE tissue. The document defines requirements and recommendations for the handling, documentation, storage and processing of FFPE specimens destined for downstream molecular in vitro diagnostic (IVD) assays and proteomic testing. It is explicitly not applicable to protein examination by immunohistochemistry (IHC).
Key topics and technical requirements
The standard covers preanalytical factors that can affect protein integrity and assay validity, including:
- Specimen collection and documentation
- Required information about the specimen donor/patient and specimen details at collection.
- Transport and reception
- Recommendations for transport conditions and laboratory reception logging to preserve molecular profiles.
- Fixation and processing
- Guidance on formalin fixation, processing and paraffin embedding of tissue; recognition that formaldehyde crosslinking alters proteins and must be considered.
- Pathology evaluation and sample selection
- Procedures for pathology review and selection of appropriate tissue regions for protein isolation.
- Protein isolation from FFPE
- Principles for isolating total proteins from FFPE tissue, including use of commercial kits or laboratory‑developed protocols; the standard notes the role of heat‑induced reversal of formaldehyde crosslinks in modern extraction methods.
- Quality assessment and storage
- Requirements for assessing quality and integrity of isolated proteins and for appropriate storage of both FFPE blocks and extracted protein.
- Preanalytical risks
- Consideration of pre‑removal events (e.g., cold ischemia) that change protein amounts (see Annex A).
- Normative references
Applications and practical value
EN ISO 20166-2:2018 is designed to improve reproducibility and reliability of molecular diagnostic and proteomic results by controlling preanalytical variability. Practical applications include:
- Standardizing workflows in molecular pathology and clinical laboratories performing protein‑based molecular IVDs.
- Guiding biobanks on FFPE collection, documentation and storage practices to preserve proteomic utility.
- Informing IVD developers and manufacturers about preanalytical requirements that affect assay performance and validation.
- Supporting regulators and quality managers evaluating laboratory processes and conformity to best practices.
Who should use this standard
- Medical laboratories and molecular pathology labs (including labs using laboratory‑developed tests)
- Biobanks and research institutions handling FFPE specimens
- IVD developers, manufacturers and regulatory authorities
- Clinical customers ordering or supplying FFPE material for proteomic analysis
Related standards
Keywords: EN ISO 20166-2:2018, FFPE, formalin-fixed paraffin-embedded, pre-examination, molecular in vitro diagnostic, isolated proteins, preanalytical, protein isolation, molecular pathology, biobank.
