Diagnostic value of serum lipocalin-2 in Egyptian patients with inflammatory bowel disease: A case-control study.

Inflammatory bowel disease (IBD), encompassing ulcerative colitis (UC) and Crohn's disease (CD), often presents diagnostic challenges. Lipocalin-2 (LCN-2) has emerged as a potential biomarker for intestinal inflammation. This study aimed to evaluate the diagnostic and clinical utility of serum Lipocalin-2 in Egyptian patients with IBD. This was a case-control study, conducted during the period between December 2024 and February 2025, involved 30 IBD patients (18 UC, 12 CD) and 30 age- and sex-matched normal controls. Serum LCN-2 levels were measured using an enzyme linked immunosorbent assay (ELISA). Clinical symptoms, disease activity (via Truelove and Witts' criteria for UC and Harvey-Bradshaw Index for CD), and routine laboratory investigations were assessed. The receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic utility, while Pearson correlation tested associations with clinical and laboratory parameters. IBD patients had significantly elevated serum LCN-2 levels compared to controls (3.15 ± 1.9 vs. 0.24 ± 0.1 ng/mL; p  <  0.001). The ROC analysis yielded an area under the curve of 0.980, with high sensitivity (96.77%) and negative predictive value (92.31%) at a cutoff of value of 0.22 ng/ml. However, LCN-2 did not significantly differ between UC and CD (p = 1.000) or across disease activity levels (p > 0.05). Notably, LCN-2 was positively correlated with disease duration (r = 0.430, p = 0.018) and platelet count (r = 0.362, p = 0.004), but showed no correlation with hemoglobin, white blood cells, erythrocyte sedimentation rate, creatinine, or glomerular filtration rate. In conclusion, according to our ROC analysis, serum LCN-2 may have an excellent diagnostic utility for identifying IBD but lacks discriminatory power between UC and CD or for assessing disease activity. Its correlation with disease duration and platelet count highlights its potential as a marker of chronic inflammation rather than acute disease severity.