Urinary Neutrophil Gelatinase Associated Lipocalin (NGAL) as a Non-Invasive Biomarker for Diagnosis of Spontaneous Bacterial Peritonitis

Background: Spontaneous bacterial peritonitis (SBP) is a severe complication in cirrhotic patients with ascites, necessitating early and accurate diagnosis. Urinary Neutrophil Gelatinase Associated Lipocalin (NGAL) has emerged as a potential non-invasive biomarker for SBP diagnosis. The aim of the study was to assess the diagnostic value of urinary NGAL in cirrhotic patients with ascites for early non-invasive detection of SBP. Methods: This cross-sectional study was conducted on 80 cirrhotic patients with ascites, divided into two groups: 40 with SBP and 40 without SBP. Urinary NGAL levels were measured, and their diagnostic performance was evaluated using receiver operating characteristic (ROC) analysis. Results: Urinary NGAL levels were significantly higher in the SBP group (2803.7 ± 1048.2 ng/dL) compared to the non-SBP group (1044.5 ± 377 ng/dL) (p < 0.001). ROC analysis revealed that NGAL had a sensitivity of 85%, specificity of 97.5%, and an area under the curve (AUC) of 0.96 at a cutoff value of >1696.5 ng/dL for diagnosing SBP. Additionally, a strong positive correlation was found between ascitic neutrophil count (ANC) and urinary NGAL levels (r = 0.81, p < 0.001). Conclusion: Urinary NGAL is a promising non-invasive biomarker for the early diagnosis of SBP in cirrhotic patients, demonstrating high sensitivity and specificity. Its incorporation into routine clinical practice could enhance the timely detection and management of SBP, improving patient outcomes.