Related Experiment Video
Updated: Jun 3, 2026

Point-of-Care Kidney and Genitourinary Ultrasound in Adults: Image Acquisition
Published on: June 21, 2024
Is urinary 5-hydroxyindoleacetic acid helpful for early diagnosis of acute appendicitis?
Ali Jangjoo1, Abdol-Reza Varasteh, Mostafa Mehrabi Bahar
1Surgical Oncology Research Center, Imam Reza Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. angjooa@mums.ac.ir
Objective:
Acute appendicitis is the most common abdominal emergency in children and young adults. There are a lot of serotonin-containing cells in the appendix, which release serotonin into the bloodstream in response to inflammation. Consequently, serotonin is converted to 5-hydroxyindoleacetic acid (5-HIAA) and secreted into the urine. On this basis, urinary 5-HIAA could be a marker for acute appendicitis. In this study, we investigated the value of 5-HIAA levels in spot urine in the diagnosis of acute appendicitis.
Methods:
The urinary 5-HIAA was measured by an enzyme-linked immunosorbent assay in the spot urine of 70 patients who presented to the emergency department with a clinical picture of acute appendicitis. Urine concentration results were correlated to final histopathologic reports, and the diagnostic value of this factor was measured.
Results:
Diagnosis of appendicitis was confirmed by histopathologic reports in 59 of 70 patients with presumptive diagnosis of appendicitis. Considering 5.25 mg/L as the cutoff point for urinary 5-HIAA, 28 patients had high urinary 5-HIAA levels, whereas 42 patients had values within reference range. The sensitivity and specificity of this test was 44% and 81%, respectively.
Conclusions:
The measurement of urinary 5-HIAA levels is not an ideal diagnostic tool for ruling out or determination of acute appendicitis.
Related Concept Videos
Appendicitis-I: Introduction
Etiology: Appendicitis can arise from various causes, primarily rooted in the obstruction of the appendix lumen. Factors contributing to this obstruction include fecal accumulation, lymphoid hyperplasia and, in...
Appendicitis-II: Diagnostic Studies and Management
Diagnosing Appendicitis
It requires a multifaceted approach, starting with a detailed physical examination to pinpoint the location and nature of the pain and identify any associated symptoms. Laboratory tests play a crucial role. A complete Blood Count (CBC) typically reveals leukocytosis (an increased number of...
Appendicitis
Acute Kidney Injury IV: Diagnostic Studies and Prevention
Imaging Studies V: Intravenous Urography and Retrograde Pyelography
Urinary Tract Infection III: Diagnostic Studies and Interprofessional Care
