ISO 4307:2021

Overview

ISO 4307:2021 - "Molecular in vitro diagnostic examinations - Specifications for pre‑examination processes for saliva - Isolated human DNA" defines requirements and recommendations for the pre‑examination handling, storage, processing and documentation of saliva specimens intended for human DNA analysis. The standard covers the pre‑analytical phase up to the start of the molecular examination and is applicable to medical laboratories (including laboratory‑developed tests), in vitro diagnostic (IVD) developers and manufacturers, biobanks, research institutions and regulatory bodies.

Key exclusions noted in the standard: saliva collected on absorbent materials or by mouth washes, native cell‑free DNA, pathogens and whole microbiome DNA in saliva are not addressed.

Key topics and technical requirements

• Pre‑examination scope: procedures from test request and patient preparation through specimen collection, transport, reception and analyte isolation prior to analytical testing.
• Specimen collection: selection and validation of saliva collection devices; donor information and instructions to reduce variability; stabilization procedures for saliva collection.
• Transport and storage: requirements for transporting saliva specimens, including guidance for devices with and without DNA stabilizers; storage temperature and duration considerations to limit DNA degradation.
• Laboratory activities: specimen reception workflow, storage of primary specimens, and documented handling practices.
• DNA isolation: requirements for isolating isolated human DNA from saliva using commercial kits or laboratory‑developed protocols.
• Quality assessment: quantitative and qualitative evaluation of isolated DNA (concentration, integrity, potential interfering substances) before proceeding to molecular assays.
• Storage of isolated DNA: conditions and documentation for short‑ and long‑term storage of extracted saliva DNA.
• Verbal forms in the document specify "shall" (requirements), "should" (recommendations) and "may/can" (permissions/capabilities).

Applications and who uses this standard

ISO 4307:2021 is practical for:

• Clinical and molecular diagnostic laboratories establishing SOPs for saliva‑based DNA tests (e.g., genetic testing, pharmacogenomics, predisposition testing).
• IVD manufacturers and kit developers validating saliva collection devices and DNA stabilizers.
• Biobanks and research groups standardizing saliva specimen collection, transport and DNA archiving.
• Regulatory authorities and accreditation bodies assessing pre‑analytical quality and compliance.
• Laboratory customers and sample collection sites implementing donor instructions and transport protocols.

Adopting ISO 4307:2021 helps minimize pre‑analytical impacts such as DNA fragmentation, degradation and bacterial overgrowth, improving reliability and reproducibility of saliva‑based molecular diagnostics.

Related standards

• ISO 15189 - Medical laboratories - Requirements for quality and competence
• ISO 15190 - Medical laboratories - Requirements for safety
  (Additional referenced standards in the document include ISO 20186‑2 and ISO 20184‑1.)