Objective To validate an existing clinical decision support tool to risk-stratify patients with acute kidney injury (AKI) for hydronephrosis and compare the risk stratification framework with nephrology consultant recommendations. Setting Cross-sectional study of hospitalised adults with AKI who had a renal ultrasound (RUS) ordered at a large. tertiary. academic medical centre. https://theplayfulcollectivees.shop/product-category/collections/