Methods for developing diagnostic criteria for conditions without objective tests, biomarkers, or reference standards: a scoping review

Background and objectives:

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.

Study design and setting:

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.

Results:

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.

Conclusion:

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.