Restoring Diagnostic Stability in Complex Illness: Integrated Longitudinal Feedback in Clinical Care (RD)

Modern healthcare produces persistent diagnostic instability in complex illness despite expanding technological capability and clinical specialization. Prior work identified structural diagnostic failure (SDF), a systemic condition where diagnostic responsibility fragments across encounters and specialties, blocking the continuous integration of clinical information across time. Under these conditions, clinical care persists-tests are ordered, referrals occur, and treatments are attempted-yet diagnostic state estimation stalls, producing repeated action without explanatory convergence.

This article examines the operational structures required to restore diagnostic stability. The proposed solution centres on restoring protected longitudinal diagnostic responsibility through two integrative clinical roles: the Doctor of Clinical Diagnostics (DCD) and the Nurse Practitioner of Clinical Diagnostics (NPCD). Clinicians in these roles are trained to synthesize evolving clinical evidence across encounters, organ systems, and specialties. They function not as replacements for specialty diagnosis but as longitudinal integrators responsible for maintaining diagnostic continuity when illness spans domains or lacks clear specialty ownership.

Within this architecture, diagnostic reasoning is preserved through integrated longitudinal feedback (ILF), a structural mechanism that maintains continuity of diagnostic information across encounters. This allows new findings, treatment responses, and patient experience to refine diagnostic understanding rather than resetting interpretation. Together, these mechanisms convert episodic encounter-based care into a closed-loop diagnostic system capable of achieving explanatory convergence in high-variance clinical environments.

The framework generates empirically testable predictions in clinical environments characterized by multisystem comorbidity and diagnostic instability. This provides a pathway for evaluating whether restoration of longitudinal diagnostic responsibility improves diagnostic convergence, reduces redundant evaluation, and stabilizes care for complex illness.