Overview
ISO 20166-1:2018 - "Molecular in vitro diagnostic examinations - Specifications for pre-examination processes for formalin-fixed and paraffin-embedded (FFPE) tissue - Part 1: Isolated RNA" provides internationally agreed guidance for the pre-examination (pre-analytical) handling of FFPE tissue intended for RNA-based molecular testing. The standard addresses how specimen collection, documentation, transport, fixation, embedding, storage and RNA isolation should be managed so that downstream molecular in vitro diagnostic assays yield reliable and clinically meaningful results.
Key Topics and Requirements
ISO 20166-1:2018 covers the pre-analytical workflow with emphasis on RNA integrity and traceability. Major technical topics include:
- Specimen collection and documentation: required information about patient/donor and specimen history to support molecular testing and result interpretation.
- Transport and reception: recommendations for safe, documented transport and logging of FFPE blocks and slides.
- Formalin fixation and processing: guidance on formalin fixation (standard buffered formalin), grossing, post‑fixation handling, decalcification, paraffin embedding and processing steps that affect RNA quality.
- Sample selection and pathology evaluation: selecting appropriate tissue regions and documenting pathology to ensure relevant RNA is analyzed.
- Isolation of RNA from FFPE tissue: principles for RNA extraction, including use of commercial kits versus in-house protocols, and laboratory practices to minimize RNase contamination.
- RNA quantity and quality assessment: requirements for assessing RNA yield and integrity prior to molecular assays (e.g., RT‑qPCR).
- Storage of FFPE material and isolated RNA: conditions and record-keeping for long‑term storage of blocks, sections and extracted RNA to preserve stability.
- Quality control considerations: an informative annex on implications of RNA quality for RT‑qPCR–based examinations.
The document uses standard ISO wording: "shall" indicates requirements, "should" recommendations and "may" permissions.
Practical Applications and Users
ISO 20166-1:2018 is directly applicable to:
- Medical laboratories and molecular pathology labs performing molecular in vitro diagnostic tests and laboratory-developed tests.
- In vitro diagnostics developers and manufacturers validating assays for FFPE-derived RNA.
- Biobanks and research institutions handling FFPE tissue for translational studies.
- Regulatory authorities and accreditation bodies assessing pre-analytical processes and quality management.
Adopting these pre-examination best practices improves RNA assay reliability, reduces pre-analytical variability, and supports regulatory compliance and clinical decision-making.
Related Standards (if applicable)
- ISO 15189:2012 - Medical laboratories - Requirements for quality and competence
- ISO 15190 - Medical laboratories - Requirements for safety
- ISO/IEC 17020:2012 - Conformity assessment - Operation of inspection bodies
- Other parts of the ISO 20166 series (see ISO website for list)
Keywords: ISO 20166-1:2018, FFPE, formalin-fixed paraffin-embedded, isolated RNA, pre-examination, pre-analytical, molecular in vitro diagnostic, RNA extraction, molecular pathology, biobank.
Open preview (PDF)Molecular in vitro diagnostic examinations — Specifications for pre-examination processes for formalin-fixed and paraffin-embedded (FFPE) tissue — Part 1: Isolated RNA
