Neutrophil gelatinase-associated lipocalin as an early marker of acute kidney injury in patients with traumatic brain injury.

BACKGROUND

Recent studies have shown that urinary neutrophil gelatinase-associated lipocalin (NGAL) is rapidly up-regulated early after murine renal injury, and in patients after cardiac surgery or patients critically ill with multiple trauma. In this study, we evaluated urinary NGAL levels as a potential biomarker of early acute kidney injury (AKI) in patients with severe traumatic brain injury (TBI).

METHODS

All patients with severe TBI admitted to our neurosurgical intensive care unit from March to September 2011 were enrolled prospectively. Urinary NGAL was measured using a chemiluminescent microparticle immunoassay upon admission and at 24 and 48 hours after TBI. The presence of AKI was defined by the Acute Kidney Injury Network (AKIN) criteria.

RESULTS

Using AKIN criteria, a total of 13 patients were identified with AKI, an incidence of 24%. Those who subsequently developed AKI had a striking rise in urinary NGAL early after TBI and a sustained increase over the entire duration of the study. The urinary NGAL level of the AKI group was significantly higher than the group without AKI at all time points. Using a cutoff value of 53.9 ng/mL, the area under the receiver-operating characteristic curve for urinary NGAL at 48 hours was 0.876 with a sensitivity of 0.69 and specificity of 0.95.

CONCLUSIONS

Increased urinary NGAL is associated with an increased occurrence of AKI in patients with severe TBI. It is possible that urinary NGAL could provide a screening tool for AKI immediately after severe TBI, and this may in turn allow early intervention to ameliorate the adverse effects of AKI.