Hardware and quality-control factors influencing digital pathology reproducibility

Digital pathology (DP) converts glass slides into whole-slide images (WSI), enabling quantitative and remote diagnostics. This systematized review examines how hardware and instrumentation (HI) form the technical basis for reliable DP. Evidence from WSI validation and engineering studies shows that section-thickness variation, staining consistency, and scanner calibration are major determinants of diagnostic reproducibility. Comparative studies consistently show that even small mechanical or optical deviations - such as micron-level thickness variation or illumination shifts - produce measurable image differences that affect both inter-site diagnostic concordance and artificial intelligence model stability. We propose a unified framework linking HI parameters to quality-control (QC) indicators and regulatory requirements, including device documentation, software validation, and metadata traceability. Integrating structured metadata from tissue processing through WSI acquisition supports reproducible, auditable, and clinically compliant DP workflows. By connecting validated WSI practice, QC mechanisms, and HI-centered standardization, this review emphasizes that reliable DP depends not only on computational methods but also on precise, well-regulated, and interoperable engineering systems.