Renal length z-score for the detection of dysfunction in children with solitary functioning kidney.

Aim: To evaluate whether renal length z-scores predict renal dysfunction in children with a solitary functioning kidney (SFK).

Methods: In a single-centre retrospective cohort of children with SFK, we correlated body mass index z-scores, extracellular volume and lean body mass to renal length z-scores. We grouped these z-scores to other markers of renal dysfunction (proteinuria, hypertension, extracellular volume and abnormal estimated glomerular function rate [eGFR]) and analysed renal length z-score with multivariate analysis, receiver-operated characteristics (ROC) plots and Youden's index to determine an appropriate cut-off.