On 24th May 2025 the Health Assembly (WHA78) officially declared rare diseases a global health priority urging governments to integrate rare-disease policies in national health plans (World Health Organisation, Rare diseases; a global health priority for equity and inclusion 2025).
A rare disease is defined as a condition which affects less than 1 in 2,000 people and there are over 7,000 rare diseases (The UK Rare Diseases Framework, 2022). Although individually uncommon, rare conditions affect about 3.5-5.9% (3.5million people) of the UK population and up to 446million people worldwide (Hguengang Wakap et al, 2020) with1 in 17 people being affected by a rare disease at some point in their lifetime. Rare diseases can be both life-limiting and life-threatening. Living with a rare disease often has a big impact on patients’ (and their families) in terms of lifestyle, finances, disability/mobility and mental health.
The UK Rare Diseases Framework, (2021) highlighted faster diagnosis for rare disease as a key priority (The UK Rare Diseases Framework, 2022), a commitment reconfirmed in the England Rare Diseases Action Plan 2025 (England Rare Diseases Action Plan 2025)
The time it takes to achieve a diagnosis of a rare disease is often referred to as the “diagnostic odyssey” as patients with rare disease face long challenging and unpredictable path to getting a correct diagnosis (Rare Disease UK, 2016). On average, patients see five doctors, receive three misdiagnoses and must wait four years before correct diagnosis (Muir,2016). Incorrect or absent diagnosis creates a barrier to appropriate care and results in potentially unnecessary and damaging treatments. The financial burden shouldn’t be underestimated, for example, a 10 year old girl endured a diagnostic odyssey for over 7 years at a cost of £356,571 before genome sequencing correctly identified her condition (Smedley et al. 2021).
Algorithms can identify patients at risk from specific rare conditions
There are ongoing advances in technology to improve patient healthcare. Algorithms can be utilised to diagnose diseases and aid clinicians with clinical decision making. This can lead to faster diagnosis for patients and improved quality of life. Importantly, algorithms can be applied at-scale, with potential to substantially reduce long-term healthcare costs.
CAPTURED will evaluate the efficacy of algorithm technology and quality improvement support, in primary care, for patients at high probability of rare or difficult to diagnose disease. The trial aims to get patients diagnosed faster and onto the correct treatment pathways.