Rapid slide-level assessment of glomerular yield using virtual staining of unstained renal biopsy sections

Renal biopsy remains the gold standard for the diagnosis of kidney diseases, and specimen adequacy is essential for reliable histopathological evaluation. However, confirmation of glomerular yield in routine pathology workflows often relies on histological sections after staining, which may delay feedback when deeper sectioning is required. In this study, we investigated whether virtual staining applied to unstained renal biopsy sections could enable early assessment of glomerular adequacy. Unstained sections prepared under different mounting conditions were virtually transformed into H&E and special stains. The visibility of glomerular structures and the reliability of glomerular assessment were evaluated across multiple scanners. Optimized preparation of unstained sections enabled stable virtual staining with preserved morphological features. Virtual special stains enhanced the visualization of glomerular basement membranes and mesangial regions, allowing reliable identification of glomeruli on unstained tissue sections. This approach demonstrated robustness across different scanning systems, outperforming direct assessment on raw unstained images. Virtual staining of unstained renal biopsy sections provides a rapid and reagent-free strategy for early slide-level assessment of glomerular yield. By enabling feedback at the sectioning stage before routine staining, this method may improve efficiency and quality control in routine renal pathology workflows.