Development of an objective, standardised tool for surgical assessment of deceased donor kidneys: The Cambridge Kidney Assessment Tool.

Quality assessment in kidney transplantation involves inspection to identify negative markers of organ-quality. However, there is a paucity of evidence guiding surgical appraisal, and currently there is no evidence to differentiate important features from those that can be safely ignored. We propose a method to standardise surgical assessment and derived a simple rule to rapidly identify kidneys suitable for transplantation. Donor and recipient data were recorded alongside clinical outcomes in a prospectively maintained database. We developed a proforma (Cambridge Kidney Assessment Tool, CKAT) and used it to assess deceased-donor kidney transplants. Factors predictive of utilisation were identified by multivariate and univariate logistic regression analysis of CKAT-assessment scores, and test performance was evaluated using standard 2x2 contingency tables. 97 kidneys were included at a single centre (2013-2014), 184 CKAT-assessments were performed. A CKAT-threshold of 'Carrell+Perfusion>3', was highly specific (99%) and performed favourably to consultant opinion (specificity 95%). 96% of the kidneys implanted in accordance with the rule survived to 1-year (mean eGFR 45.3ml/min/1.73m ). To our knowledge, this is the first attempt to objectively define macroscopic features that are relevant to kidney utilisation. Common language could support training in organ assessment and ultimately help address unnecessary discard of donor kidneys.