Acute renal failure: the interest in new biomarkers

Abstract

Acute renal failure (ARF) is the generic term used to describe a rapid decrease in the glomerular filtration rate (GFR), as well as its consequent effects on nitrogenous wastes. Current definitions of ARF take into account urine output and increase in serum creatinine levels. If occurring rapidly, oliguria and anuria may correspond to both renal changes as result of hypovolaemia and presence of severe ischemic injuries. Serum creatinine is a marker for variations in GFR, which is neither sensitive or accurate. In addition, its increase is delayed following renal damage. Thus, in order to provide an early diagnosis of ARF and to detect renal damage or tubular injuries, a number of functional and lesional markers have been developed. Plasma and urine NGAL (neutrophil gelatinase-associated lipocalin) and cystatin C concentrations as well as urine as KIM-1 (kidney injury molecule-1) and NHE3 (sodium-hydrogene exchanger type 3) concentrations have been proposed as valuable biomarkers; however, results from confirmatory trials are still not available. In this review, we will discuss the limits in the current definitions of serum creatinine concentrations, the current results obtained with the new biomarkers, and the major concerns that may limit their use and interpretation of the available data.