ISO 19238:2023

Overview

ISO 19238:2023 - "Radiological protection - Performance criteria for service laboratories performing biological dosimetry by cytogenetics - Dicentric assay" - is the third-edition ISO standard that defines performance, quality assurance and accreditation criteria for service laboratories performing biological dosimetry using the dicentric chromosome assay with manual scoring. The standard covers procedural, safety, statistical and reporting requirements needed to produce reliable dose estimates from unstable chromosome aberration frequencies.

Key topics and technical requirements

• Scope and responsibilities: Roles and obligations of the requestor and the service laboratory, including sample coding and handling.
• Confidentiality and data security: Protection of personal information, transmission, storage, anonymity and a required data security plan.
• Laboratory safety: Microbiological, chemical and optical safety expectations for cytogenetic work.
• Sample processing and scoring: Culture, slide preparation, coding, and procedures for manual scoring of first‑division metaphases and scorer qualification.
• Calibration curves and reference doses: Requirements for calibration sources, dose ranges and establishment of dose–response curves used to convert dicentric frequency into absorbed dose.
• Statistical evaluation: Testing aberration distributions, minimum detectable dose, confidence limits, dose estimation and uncertainty analysis (including low‑dose fitting by maximum likelihood and odds‑ratio methods described in informative annexes).
• Reporting: Required report content, interpretation guidance and sample report templates (Annex C).
• Quality assurance / quality control (QA/QC): Setup and maintenance of a QA programme, inter‑laboratory performance checks, scorer requalification, sample integrity checks and instrumentation QC.
• Informative annexes: Practical tools such as requestor instructions (A), questionnaires (B), sample report (C), statistical methods (D–F) and data sheets (G).

Practical applications

ISO 19238:2023 is designed to ensure consistent, reliable biological dose assessments in situations including:

• Occupational or accidental radiation overexposure investigations
• Emergency response and public health incident evaluation
• Retrospective dose assessment for clinical, research or regulatory purposes

By standardizing procedures for manual dicentric scoring, calibration and QA/QC, the document improves comparability of dose estimates across laboratories and supports timely, defensible decision‑making.

Who uses this standard

• Cytogenetics and biological dosimetry laboratories seeking accreditation
• Laboratory managers and quality officers implementing QA/QC programs
• Radiation protection professionals and emergency response teams
• Regulators and accreditation bodies assessing laboratory competence

Related standards

• ISO 19238:2023 replaces ISO 19238:2014 (second edition) and was prepared under ISO/TC 85 (Radiological protection). Laboratories should also consult other radiological protection and laboratory management standards relevant to accreditation and safety.