Exact measurement of glomerular filtration rate (GFR) is complex in the clinical setting and thus GFR is usually estimated from serum creatinine levels through creatinine-based equations such as the MDRD or the CKD-EPI equations. Particularly, this is the case in kidney recipients with DGF, in whom creatinine levels remain high and they have to undergo dialysis. Creatinine is dialyzable, so that it cannot reflect the actual renal function in this setting due to fluctuations of its levels. Thus there is emergent need for a more accurate renal biomarker.