The Red Dot System in X-Ray Interpretation: Development and Effectiveness

The red dot system, more recently known as a ‘Radiographer Abnormality Detection System’ (RADS), is a simple yet effective procedure that was first proposed by Berman et al. in the early 1980s. The system was developed as an attempt to reduce diagnostic errors in the emergency department by affixing a red sticker to plain X-ray films that radiographers believed to be abnormal. The red sticker acted as a visual cue, alerting the referrer to a potential abnormality.

The red dot system has been widely adopted in the United Kingdom, with a study in 2008 finding that 92% of emergency departments utilized some form of RADS within their radiography department. Furthermore, research in 2011 conducted by the same authors found a small decrease in this statistic to 88.6%. The United Kingdom’s extensive use of RADS has not only improved the diagnostic process but has also had a positive impact on emergency management by supporting junior medical doctors in interpreting radiographs of trauma patients.

However, the accuracy of the red dot system in detecting undisplaced fractures is significantly reduced, with a sensitivity of 45.9% and a positive predictive value (PPV) of 74.8%. This suggests that while the red dot system can be effective in detecting certain abnormalities, it may not be as reliable in detecting more subtle pathology.

Despite its limitations, the red dot system has been widely adopted and has had a positive impact on emergency management by supporting junior medical doctors in interpreting radiographs of trauma patients. It provides a time-efficient overlap between emergency referrers and radiographers when assessing a plain radiographic image.

Recently, several limitations have been identified with the red dot system, which has led to the evolution of a radiographer commenting system. In this system, a radiographer provides a brief description of abnormalities identified in emergency healthcare settings.

A study investigating radiographers’ participation in abnormality detection systems and their perceptions of benefits, barriers and enablers to radiographer commenting found that a range of factors are likely to contribute to the successful implementation of radiographer commenting in addition to abnormality detection in emergency settings. Effective image interpretation education amenable to completion by radiographers would likely prove valuable in preparing radiographers for participation in abnormality detection and commenting systems in emergency settings.

In conclusion, the red dot system has been found to be effective in detecting certain abnormalities in radiographs but may not be as reliable in detecting more subtle pathology. Despite its limitations, the system has been widely adopted and has had a positive impact on emergency management. The evolution of the radiographer commenting system may provide additional benefits and improve the accuracy of radiograph interpretation in emergency settings.

Practitioner Development UK (PDUK) is a leading provider of continuing professional development (CPD) courses for healthcare professionals. We offer a wide range of courses, delivered both virtually and in-house.

We highly recommend our CPD Standards Office (CPDSO) X-ray interpretation course of minor injuries. This workshop links clinical presentation with relevant anatomy and principles of x-ray interpretation. Patient assessment, radiographic referral, interpretation and treatment for minor injuries are all included.

Practitioners should ideally be working in an environment where X-ray interpretation is part of their role, but it may be suitable for practitioners who make referrals for X-rays at another location.