Urinary kidney injury biomarkers and urine creatinine normalization: a false premise or not?

Substantial research has focused on the discovery of urinary biomarkers to detect acute kidney injury (AKI) before a rise in serum creatinine. As in chronic kidney diseases, the concentrations of urinary AKI biomarkers have been normalized to urine creatinine concentration to account for creatinine clearance and urine flow. Waikar et al. challenge the assumption that normalization to creatinine clearance in a chronic disease state can be extrapolated to an acute state, in which creatinine clearance is, by definition, changing acutely.