What is the role of novel biomarkers for the diagnosis of intrinsic Acute Kidney Injury
A number of potential novel urine and serum biomarkers have been investigated for the diagnosis and classification of Acute Kidney Injury, including cystatin C, NGAL, KIM-1, liver fatty acid binding protein (L-FABP), interleukin-18, insulin-like growth factor binding protein 7 (IGFBP-7), and tissue inhibitor of metalloproteinase-2 (TIMP-2).
Cystatin C is a marker of glomerular filtration that has a shorter serum half-life than creatinine and therefore increases more rapidly in the setting of Acute Kidney Injury than creatinine does.
Cystatin C is normally completely reabsorbed in the urine so there is no urinary excretion; in the setting of Acute Kidney Injury, urinary cystatin C is increased as a result of tubular dysfunction. NGAL, KIM-1, L-FABP, and interleukin-18 are markers of tubular injury, and plasma and urine levels increase with intrinsic Acute Kidney Injury.
However, none of these markers are available for clinical use. IGFBP-7 and TIMP-2 are markers of cell cycle arrest; urine levels of these markers have been found to increase in patients at increased risk for Acute Kidney Injury.
A urine test incorporating these markers is clinically available; however, the optimal use of this technology remains uncertain.
