Significance of Neutrophil Gelatinase-Associated Lipocalin Level as an Acute-Phase Reactant in Patients with Systemic Inflammatory Response Syndrome

ABSTRACT

BACKGROUND: We investigated the significance of plasma neutrophil gelatinase-associated lipocalin (pNGAL) level as an acute-phase reactant and an index for an increase in serum creatinine (sCr) level in patients with inflammatory diseases. METHODS: A total of 63 patients with systemic inflammatory response syndrome (SIRS) and 149 without SIRS were evaluated, and pNGAL level was determined using a fluorescence immunoassay. sCr levels were measured daily during three days, and the difference between the initial and follow-up sCr levels was defined as a delta sCr value. Serum albumin/sCr ratio (sACR) was calculated. High-sensitivity C-reactive protein (hsCRP) level was determined using a latex turbidometric method. RESULTS: The median pNGAL level in the SIRS group (154 ng/mL) was significantly higher than that in the non-SIRS (86 ng/mL) and control (62 ng/mL) groups (P<0.001, respectively). The area under the ROC curve (AUC) of pNGAL for diagnosing SIRS was 0.725 (95% CI, 0.664-0.781), which was not significantly different from that of hsCRP (0.749; 95% CI, 0.685-0.809; P=0.375). Multivariate regression analyses revealed that log-pNGAL was significantly associated with hsCRP (beta=0.546, P<0.001) and sACR (beta=0.351, P<0.001). The AUC of pNGAL for the positive delta sCr in 48-72 hr was 0.649 (95% CI, 0.542-0.746, P=0.023) in the SIRS group. CONCLUSIONS: pNGAL is comparable to hsCRP as an inflammation-related parameter, and its measurement may provide additional information for a potential increase in sCr during 48-72 hr in patients with SIRS.