Purpose of the classification
The ILO international classification provides a systematic way to record radiographic appearances associated with pneumoconiosis. It is used in surveillance of dust-exposed workers, epidemiological research and comparisons between findings. Its purpose is to describe an image using a common language, rather than to turn an isolated chest radiograph into a complete explanation of an individual’s health.
What it records
Readers assess technical quality and characteristics of opacities, including shape, size and profusion. The system also describes pleural changes and other findings through specified conventions. These categories are not a general scale of fitness for work or a percentage disability rating. Interpretation requires specific training and comparison with the appropriate standard reference images, rather than an informal visual judgement.
Reference images and edition
The 2022 revision introduced a new set of digitally acquired standard images. The ILO distinguishes DICOM files for classification in a clinical environment from JPEG images intended for teaching or information. A screenshot, compressed picture or unsuitable display should not become an improvised substitute for the required reference material and viewing conditions. The edition and image source therefore matter for both reproducibility and valid comparison.
Classification is not diagnosis
Diagnosing a dust-related disease requires exposure history, clinical assessment and appropriate investigations. Classification alone cannot identify the responsible substance or exclude other conditions. For example, someone exposed to respirable crystalline silica needs an assessment consistent with exposure, symptoms and follow-up, alongside radiographic description where indicated. These are complementary steps with different purposes and clinical responsibilities.
Quality and reader differences
Readers may disagree even when using common criteria. Training, display conditions, quality assurance and independent readings help limit variability. NIOSH B Reader certification demonstrates proficiency in this classification within its programme. It is neither a universal medical licence nor a substitute for the professional requirements in the country where the assessment takes place. Programme rules must retain their jurisdictional context.
Responsible use of the report
A report should identify the classification used and separate radiographic description from clinical conclusions. Significant findings need an appropriate clinical pathway and communication. ILO categories do not establish entitlement to compensation, which depends on the applicable framework. Results from other imaging techniques should not be compared directly with radiographic classifications as though they were interchangeable measures of the same finding.
