Early diagnosis of AKI currently depends on detection of reduced kidney function by the rise in serum creatinine concentration, an unreliable measure in the acute setting. This article discusses the pros and cons of emerging early biomarkers which may prove useful.

NGAL (neutrophil gelatinase-associated lipocalin) has become hot news as an early marker of renal injury. However, like many other endogenous biomarker molecules, it is not produced by just one cell type and different pathologies in different tissues can all provoke responses. Results must be interpreted with due regard to concurrent conditions in the individual patient to make the optimal use of this sensitive marker.

NGAL, or neutrophil gelatinase-associated lipocalin, is a small, robust protein expressed by neutrophils and various epithelia, including the renal proximal tubules. While initially proposed as a marker for infections and certain adenocarcinomas, it is now apparent that its early and dramatic rise in urine after renal injury may make it a useful marker of such injury.