Neurophil gelatinase-associated lipocalin as a new biomarker in laboratory medicine

Neutrophil gelatinase-associated lipocalin (NGAL) is a 25 kDa protein of the lipocalin superfamily. This protein is expressed and secreted by immune cells, hepatocytes, and renal tubular cells in various pathologic states. NGAL has recently generated great interest as an early biomarker of renal injury. However, like many other endogenous biomarkers it is not produced by just one cell type and it exists in more than one molecular form. As recent research has shown different pathological conditions may involved in the production of this molecule. This review summarizes the current knowledge about the biology of NGAL and examines the role of this molecule of acute renal injury as well as in other pathologic conditions like neoplasia, anemia, pregnancy, cardiovascular disease chronic kidney disease and in cardiorenal syndrome. Commercial and research immunoassays are used to measure NGAL in both plasma and urine but these assays are not standardized. The existence of different molecular forms of NGAL and their expression at various disease states further complicates the interpretation of the results. Pre analytical issues and biological variation are also not fully elucidated.