Controversies in chronic kidney disease staging.

In 2002, a new chronic kidney disease staging system was developed by the US National Kidney Foundation. The classification system represented a new conceptual framework for the diagnosis of chronic kidney disease (moving to a schema based on disease severity defined by the glomerular filtration rate). While the introduction of the staging system stimulated significant clinical and research interest in kidney disease, there has been vigorous debate on its merits. This mini-review aims to summarise the recent controversies that have been raised since the introduction of the new classification.