Diagnosis is the process of identifying a disease, condition, or injury from its signs and symptoms. It is essential for service users to receive the required care and treatment for their illness; however, errors can occur at any stage of the process. The World Health Organization (WHO) defines a diagnostic error as one that emerges when a diagnosis is missed, inappropriately delayed, or wrong (incorrect), and results in a failure to communicate the explanation of the service user’s health problem.

Diagnostic errors are a leading cause of preventable harm in service users, with the potential for serious harm, making them a global priority in patient safety. Deficiencies in referral pathways, delays in ordering and interpreting tests, issues with clinical assessment, communication failures, and cognitive errors are some of the contributing factors resulting in diagnostic errors. A review of adverse events in Irish hospitals reported that just over a quarter of diagnostic-related adverse events were considered preventable. NIMS data shows that claims related to the sub-hazard type ‘diagnosis’ ranked second by number of service user claims received by the State Claims Agency in 2023 related to publicly-funded acute care, with an estimated liability of almost €110 million. The State Claims Agency's analysis shows that claims can arise due to deficits in the diagnostic process, e.g., in assessment/developing a differential diagnosis, delays/failures in performing diagnostic tests and investigations, failure to follow-up on diagnostic tests, and ordering the incorrect diagnostic tests. These deficits can result in the delayed or missed diagnosis of cancer, of lesions on imaging, of fractures, of infections, and of other conditions.

The theme for the WHO’s World Patient Safety Day, 2024, is ‘Improving diagnosis for patient safety - Get it right, make it safe!’. In line with its statutory risk management mandate, the State Claims Agency has prepared this infographic to disseminate learning and raise awareness of the risk of diagnostic errors that result in harm.

Learning from reported incidents

Incident reporting affords health and social care services the opportunity to learn from adverse incidents. In Ireland, publicly funded health and social care services have a statutory obligation to report incidents to the State Claims Agency on NIMS, including those involving diagnosis.

Enhancements to NIMS implemented in December 2021 aimed to standardise reporting of incidents to improve data quality, and enabled capture of diagnosis incidents. These incidents are now captured under the sub-hazard category field for ‘diagnosis’. The data presented here represent service user clinical care incidents for the sub-hazard category diagnosis reported on NIMS over a two-year period, 2022-2023, by publicly-funded health and social care services. Based on the analysis of these incidents, we have prepared advice to improve practice and reduce the risk of adverse outcomes due to diagnostic error during clinical care.

What does our analysis show?

• 77.9% of diagnosis incidents were reported with a negligible (no harm) severity rating.
• 79.2% were reported as a delayed diagnosis, frequently related to delayed access to diagnostic services or delays in receiving diagnostic results.
• In 55% of incidents the cause was reported as ‘not performed when indicated’. This was followed by ‘incomplete/inadequate’ (29%), and the majority of these related to documentation or communication issues.
• 52% of incidents were reported by stage of process as ‘test/investigations’. Whilst this indicates that diagnostic services should pay heed to their internal flow process to ensure timely access and reporting, it should also be noted that sampling issues accounted for some of these incidents. These included specimen/blood labelling errors, wrong blood in tube, incorrect service user identification, and discrepancies with accompanying paperwork; most required a repeat sample to be obtained, causing a delay.
• There was a 19.3% increase in diagnosis incidents reported in 2023 compared to 2022, mainly related to delayed diagnosis. This is in line with an overall increase in reporting of clinical care incidents, reflecting positive engagement with NIMS.
• 41.5% of diagnosis incidents were reported by nursing and midwifery staff, 32.0% by allied health professionals, and 15.6% by medical staff, indicating the valuable role these staff groups play in identifying and reporting diagnosis incidents. However, the average time to report an incident was 57 days, signalling delays in reporting; this is an area for improvement.

How can diagnostic safety be improved?

Arriving at an accurate diagnosis, and ensuring service users receive correct and timely interventions, requires competence in clinical judgment and technical skills, functioning care pathways, and effective communication between health and social care professionals and with service users. Diagnostic errors are often complex in origin, and consideration should be given to a range of mechanisms to minimise the risk of their occurrence. Health and social care services as well as health and social care professionals have important roles to play in improving diagnostic safety. Based on the findings above and best practice, the State Claims Agency has prepared the following advice:

Health and social care services:

1. Enhance and develop care processes and systems, involving service users and their families, that ensure timely assessment, timely access to diagnostic testing and information, and communication and follow up of results.
2. Ensure that health and social care professionals have and maintain the competencies needed for effective performance of diagnostic procedures, including access to education and training in the diagnostic procedures relevant to their role, aligned with regulatory, professional and/or accreditation requirements. Training in cognitive biases to facilitate more effective decision-making should also be considered, where appropriate.
3. Where resources allow, invest in health information technologies that support the diagnostic process, such as point-of-care-testing barcoding systems; computerised diagnostic decision-making support systems; advanced automated imaging and diagnostic tools; trigger algorithms, including computer based and alert system; and result notification systems.
4. Risk assess services to ensure continuity of service user care, including evaluating management processes such as triage, workflow, management of inadequate capacity and excess workload, and alternative pathways to address delays from unexpected increase in demand.
5. Audit quality assurance metrics relating to the provision of diagnostic services such as turnaround times to ensure alignment with service user requirements and organisational objectives, as well as regulatory requirements.
6. Educate health and social care staff regarding the need to report and learn from incidents using NIMS in a timely manner.

Health and social care professionals

1. When ordering diagnostic tests, including laboratory or radiological investigations, ensure all details, such as the clinical indication, laterality, and the test required, are accurate.
   • For further State Claims Agency guidance, please the following Patient Safety Notifications:
     • Patient Safety Notification: Getting Diagnostic Imaging Right
     • Patient Safety Notification: Recording and Documentation in the Health Care Record

1. For further State Claims Agency guidance, please the following Patient Safety Notification:
   1. Patient Safety Notification: Service User Identification - Getting it Right

References are available on request.