Plasma and urine NGAL was monitored (daily to alternate days) in 135 consecutive patients admitted to intensive care. ARF was defined as a 50% or greater increase in plasma creatinine over basal values. Nine patients were excluded because of incomplete data, e.g. due to early transfer. NGAL was determined with a commercially available ELISA kit (AntibodyShop A/S, Denmark). Maximal NGAL levels in patients with and without ARF groups were analyzed nonparametrically by the Mann-Whitney test. Data are reported as median (interquartile range).

Patients were admitted with one or more serious conditions including sepsis, complications of cancer, ruptured aortic aneurysm and multiple trauma (postoperative). Analyzed independently of concurrent or causative conditions, the maximal urinary NGAL level was significantly (p<0.0001) higher in the 58 patients with ARF (2693 (4381) ng/mL) than in the 68 patients without ARF (53 (171) ng/mL). The maximal plasma NGAL was also significantly (p<0.0001) higher in the patients with ARF (947 (1008) ng/mL) than in the patients without ARF (215 (203) ng/mL). The biggest difference in the median values of the two groups was seen in urine (51-fold higher value in ARF) as compared with the 4.4-fold higher median value seen in plasma. Mortality during admission was 36% for patients with ARF and 3% for patients without ARF.

It is concluded that NGAL is dramatically increased in the urine of unselected critically ill patients with ARF, which is associated with a higher mortality. Urinary NGAL determination may therefore be useful for the diagnosis of renal injury leading to ARF in patients admitted to intensive care.