Methods for developing diagnostic criteria for conditions without objective tests, biomarkers, or reference...

Diagnostic criteria play an important role in informing clinical decision-making, particularly for conditions lacking objective tests, biomarkers, or reference standards. Despite their importance, there is no established methodological guidance for developing diagnostic criteria. This scoping review aimed to identify and describe the methodological approaches used to develop diagnostic criteria in the absence of objective tests, biomarkers, or reference standards.

We conducted a scoping review in accordance with JBI methodology and the PRISMA-ScR reporting guideline. Studies published between 2000 and 2024 that described methods used to develop diagnostic criteria for conditions without objective tests, biomarkers, or reference standards were included. A comprehensive search was performed across multiple databases and supplemented with gray literature searches and expert consultation. Data were extracted independently by two reviewers and synthesized using descriptive statistics and qualitative content analysis.

We included 139 studies. Suboptimal reporting of methodology was a barrier to assessment of methodological credibility. Authors used one or more of three main approaches to develop diagnostic criteria: consensus-based, literature-based, and/or primary study-based. Consensus methods were used in 98/139 (71%) of studies, with Delphi or modified Delphi approaches being the most commonly adopted. The role of evidence in diagnostic criteria development was not described in 36/139 (26%) of the included studies. In studies using consensus methodology to develop diagnostic criteria, prospective approaches to ensuring appropriate diversity among the diagnostic criteria development panel were employed in only 5/98 (5%) of studies and patient/advocate consultation was performed in 18/98 (18%) of studies.

Methodological approaches to developing diagnostic criteria for conditions without objective tests or standards are variable, inconsistently reported and often lack a clear evidence base. This could be aided by development of specific methodological guidance.

When lab tests or scans are not available to confirm a diagnosis, doctors may use diagnostic criteria to help them decide what condition a patient may have. There is currently no clear way to create these criteria, which can lead to inconsistency and confusion. We looked at why this matters-because diagnostic criteria developed without transparency or methodological rigor may lead to incorrect diagnosis, patient harm or inequitable access to care-and explored how researchers develop diagnostic criteria when an objective test does not exist. Most studies relied on expert meetings, but many did not explain how they chose experts, gathered evidence or involved diverse perspectives such as patient voices. Our research shows that current practices often are not well explained and may be biased or incomplete. By understanding what's missing and what may work, we hope this study encourages better, more transparent methods so that future diagnostic criteria are clearer, fairer, and more trustworthy for both patients and healthcare providers.