A small polypeptide, neutrophil gelatinase-associated lipocalin (NGAL), is one of the most promising and best-studied AKI biomarkers (Mishra.et al.,2003; Devarajan.et al 2003) The expression of NGAL was predominantly in proliferating and regenerating tubular epithelial cells, which suggested a role in repair. (Mori.et al.2005) The majority of NGAL, secreted by injured renal tubule epithelial cells, is in a 25kDa monomeric form. In contrast, neutrophils have been claimed to release NGAL primarily as a 45kDa homodimer, i.e. two NGAL monomers linked by a disulfide bridge. It also exists as a 135-kDa heterodimer, covalently conjugated with gelatinase (Cai.et al.2010) NGAL is easily detected in blood and urine due to its small size and resistance to degradation. It can be measured non-invasively using routine laboratory analysers as well as some point of care devices. Furthermore, NGAL concentration in both urine and plasma rises rapidly in a dose-dependent manner that is proportional to the degree of acute kidney damage (Haase-Fielitz.et al.2009)