A Prospective Comparative Study on the Clinical Diagnostic Performance of Blood Inflammatory Markers in Acute Appendicitis

Objective: Despite the substantial advancements in imaging techniques for the diagnosis and differential diagnosis of acute appendicitis (AA) over recent decades, the specificity and sensitivity of widely utilized laboratory biomarkers in clinical practice remain inadequate.This study aimed to investigate the diagnostic utility of commonly employed blood inflammatory markers for AA. Methods: A total of 399 participants who either sought medical care or underwent health examinations were enrolled in this prospective study. The cohort comprised 200 patients diagnosed with AA (AA group), 100 patients presenting with abdominal pain but without AA (AP group), and 99 healthy individuals undergoing routine health check-ups (HC group). For all subjects, the following biomarkers were measured: plasma neutrophil gelatinase-associated lipocalin (NGAL), white blood cell count (WBC), neutrophil count (NEU), percentage of neutrophils (NEU%), neutrophil-to-lymphocyte ratio (NLR), and C-reactive protein (CRP). The diagnostic performance of the observed indicators, both individually and in combination, was assessed for the diagnosis of AA using Receiver Operating Characteristic (ROC) curves analysis and Delong's test. Results: The laboratory indicators demonstrated a progressive increase from the HC group to the AP group, and further to the AA group (all p<0.05). Multifactorial logistic regression analysis identified NEU% and plasma NGAL as significant risk factors for the occurrence of AA. ROC curve analysis and Delong's test indicated that, in distinguishing the AA group from the HC group, the diagnostic performance of plasma NGAL, CRP, and NLR was equally substantial and superior to that of NEU and WBC. Within the AP group, plasma NGAL and CRP exhibited comparable diagnostic efficacy, outperforming NEU, WBC, and NLR. When differentiating AA in the non-appendicitis group (ie HC group + AP group), NGAL and CRP demonstrated comparable diagnostic efficacy, surpassing that of NEU, white WBC, and NLR. While the integration of multiple diagnostic tests can potentially improve overall diagnostic accuracy, the observed enhancement in the AUC is not statistically significant. Conclusion: NGAL, CRP, WBC, NEU% and NLR were significantly increased in patients with acute abdomen. NGAL and NEU% may function as independent risk factors for predicting the incidence of AA, with NGAL and CRP demonstrating similar and favorable diagnostic performance. While the combined evaluation of these biomarkers may enhance the diagnostic value for AA, the improvement in the area under the curve (AUC) is not substantial.