Distinguishing elevations of serum creatinine with biomarkers of kidney tubular health. Elevations in serum creatinine that meet the clinical definition of AKI do not necessarily represent true injury and have differing significance and clinical implications depending on the clinical milieu. Biomarker changes, their significance in elucidating the meaning of seemingly uniform elevations of serum creatinine, and clinical implications for patient management are detailed for the settings of postcardiac surgery, cardiorenal syndrome, hepatorenal syndrome, and kidney transplantation. Abbreviations: AKI, acute kidney injury; IL, interleukin; KIM-1, kidney injury molecule-1; NGAL, neutrophil gelatinase-associated lipocalin.