Neutrophil Gelatinase Associated Lipocalin (NGAL), a 25 kDa member of the Lipocalin family expressed by the renal tubular epithelium, is released into both urine and blood in response to tubular injury. Higher plasma NGAL has been associated with poorer clinical outcomes in AHF . A number of small studies showed conflicting findings on the potential value of plasma NGAL as an early marker of WRF . For instance, in 207 patients with AHF, neither serum creatinine nor NGAL was able to accurately predict WRF . In sharp contrast, in another study in 119 AHF patients, NGAL (below a certain cutoff value) had a 100% negative predictive value for the prediction of WRF . A recent study evaluating NGAL as a predictor of acute kidney injury (AKI) showed similar results for NGAL, compared with serum creatinine, in the ability to predict AKI . In the present study, we aimed to establish the value of plasma NGAL as an early predictor of WRF, and as a discriminator between WRF with a good and a poor prognosis.