LAUSR

Background Acute appendicitis is one of the most common abdominal emergencies. Despite all improvements in diagnostic techniques, there are still ongoing problems as proper diagnosis, misdiagnosis and perforated appendicitis. The aim of this study is to demonstrate the clinical value of IMA in patients with appendicitis and to determine the accurate diagnosis of appendicitis in clinically suspected patients. Methods Pediatric patients with acute abdominal pain who had the Pediatric Appendicitis Score (PAS) ≥ 7 ( n  = 109) and a control group of 35 patients were included in this prospective case–control study. Patients were divided into two groups: patients with appendicitis (pathologically confirmed) ( n  = 78) and no appendicitis ( n  = 31). No appendicitis included observation patients and negative appendectomy. Serum samples were collected for routine laboratory parameters and IMA before surgery. Results Patients with appendicitis had significantly higher IMA levels than no appendicitis and control groups ( p  = 0.001 and p  < 0.001; respectively). Moreover, patients with negative appendectomy had significantly lower IMA levels than patients with appendicitis ( p  = 0.009). IMA and PAS were used together, and in the ROC analysis, we obtained 0.81 AUC for PAS and 0.89 AUC for PAS and IMA. Conclusion The current study indicated that IMA is a reliable marker for accurate diagnosis of appendicitis. The combination of IMA with PAS score has been shown to facilitate the diagnosis of appendicitis.