The use of plasma and urine neutrophil gelatinase associated lipocalin (NGAL) and Cystatin C in early diagnosis of septic acute kidney injury in critically ill patients

AIM: To assess and compare the roles of plasma and urine concentrations of neutrophil gelatinase associated lipocalin (NGAL) and Cystatin C for early diagnosis of septic acute kidney injury (AKI) in adult critically ill patients. METHODS: Patients were divided into three groups as sepsis-non AKI, sepsis-AKI and non sepsis-non AKI. Plasma samples for NGAL and Cystatin C were determined on admission and on alternate days and urinary samples were collected for every day until ICU discharge. RESULTS: One hundred fifty one patients were studied; 66 in sepsis-non AKI, 63 in sepsis-AKI, 22 in non-sepsis-non-AKI groups. Although plasma NGAL performed less well (AUC 0.44), urinary NGAL showed significant discrimination for AKI diagnosis (AUC 0.80) with a threshold value of 29.5 ng/ml (88% sensitivity, 73% specificity). Both plasma and urine Cystatin C worked well for the diagnosis of AKI (AUC 0.82 and 0.86, thresholds 1.5 and 0.106 mg/L respectively). CONCLUSION: Plasma and urinary Cystatin C and urinary NGAL are useful markers in predicting AKI in septic critically ill patients. Plasma NGAL raises in patients with sepsis in the absence of AKI and should be used with caution as a marker of AKI in septic ICU patients.