Table 1.

Entities of acute kidney injury syndrome

A. No AKI (RIFLE-negative and biomarker-negative)	B. AKI with filtration dysfunction (RIFLE/AKIN/KDIGO-positive)
C. AKI with tubular damage (biomarker-positive) = 'subclinical AKI'	D. AKI with tubular damage (biomarker-positive) and filtration dysfunction (RIFLE/AKIN/KDIGO-positive)

The dimensions of A, B, C, and D and the combinations of tubular damage and dysfunction are difficult to add to the existing RIFLE (Risk, Injury, Failure, Loss, and End-stage kidney disease) graph. They are best displayed in a contingency table such as the one above. So, in the future, both graphs (RIFLE graph and contingency table) should probably be displayed and used for acute kidney injury (AKI) diagnosis. AKIN, Acute Kidney Injury Network; KDIGO, Kidney disease: Improving Global Outcomes.