Diagnostic performance of urinary 5-Hydroxyindoleacetic Acid in acute appendicitis:a systematic review and diagnostic test accuracy meta-analysis

BackgroundThis study aimed to analyze the diagnostic performance of urinary 5-Hydroxyindoleacetic Acid (5-HIAA) in acute appendicitis (AA). MethodsWe conducted a systematic review of the literature in the main databases of medical bibliography. Two independent reviewers selected the articles and extracted relevant data. Methodological quality was assessed using the QUADAS2 index. A synthesis of the results, standardization of the metrics, and a random-effect meta-analysis were performed. Additionally, a diagnostic test accuracy meta-analysis (DTA) was performed. ResultsTwelve studies with data from 1467 participants (724 patients with a confirmed diagnosis of AA and 743 controls) were included in this review. The random-effect meta-analysis of urinary 5-HIAA (AA vs controls) included 7 articles (352 AA and 258 controls) and resulted in a significant mean difference [95% CI] of 23.30 [15.82-30.77] mol/L (p<0.001). The DTA meta-analysis of urinary 5-HIAA included 8 articles and resulted in a pooled sensitivity [95% CI] of 68.6 [44.1-85.9]% and a pooled specificity [95% CI] of 82 [54.7-94.5]%. ConclusionsAlthough the evidence is heterogeneous and limited, urinary 5-HIAA emerges as a potential non-invasive diagnostic tool for AA. Urinary 5-HIAA does not seem to be a useful biomarker to distinguish between NCAA and CAA. Future prospective studies with a large sample size and a rigorous design are necessary to validate these findings.