The differential count of diagnostic expertise: A phenomenological study into complexity and its implications for medical education

Background Diagnostic practice across clinical specialties has become increasingly complex as clinicians integrate descriptive observations, imaging, and molecular data within technologically advanced and collaborative environments. These changes demand an increasing variety of skills that extend beyond traditional models of technical competence. Yet postgraduate medical education has been slow to adapt, continuing to prioritise standardised assessments and procedural knowledge. Haematology provides a salient case: diagnostic reasoning here requires the synthesis of morphological, immunophenotypic, cytogenetic, and molecular information into a coherent clinical interpretation within the context of a diagnostic field that is growing rapidly. This study explores how experienced haematologists make sense of diagnostic complexity and how their insights might inform postgraduate education. Methods An interpretivist–constructivist qualitative design was employed using Interpretative Phenomenological Analysis (IPA). Five consultant haematologists from centres in Ireland, the United Kingdom, France, and the Netherlands participated in semi-structured online interviews (60–90 minutes). Participants were purposively and snowball-sampled through professional networks. Sample size was guided by Malterud’s concept of informational power, recognising that a focused research question and high participant expertise permit rich analysis from a small cohort. Interviews were transcribed verbatim and analysed iteratively to identify experiential themes, with ongoing reflexive dialogue between a clinician-researcher and a medical-education researcher. Ethical approval was granted by the St Vincent’s University Hospital Ethics Board (RS25-007). Results Three interrelated themes were identified: Diagnosis as a lived, integrative act : diagnostic reasoning was experienced as embodied, iterative, and relational, involving perceptual synthesis across modalities and negotiation between structured systems and tacit judgement. Judgement, trust, and the weight of knowing : diagnosis carried ethical and emotional dimensions; clinicians cultivated trust through openness about uncertainty and recognised subjectivity as intrinsic to expertise. Reconfiguring expertise in the age of genomics and AI : participants described adapting to computational and genomic innovations while maintaining a human, interpretive stance toward diagnostic meaning. Conclusions Experienced haematologists conceptualise diagnosis not as a technical algorithm but as an interpretive practice grounded in embodied perception, ethical awareness, and epistemic humility. Postgraduate training should therefore include reflective spaces that legitimise uncertainty, encourage collaborative reasoning, and foster the narrative and integrative capacities required for modern diagnostic work.