Prospective Comparison of Pro-Adrenomedullin, C-Reactive Protein, and Neutrophil-to-Lymphocyte Ratio for Diagnosing Acute Appendicitis

This prospective, single-center, observational study aims to evaluate the diagnostic accuracy of serum pro-adrenomedullin (Pro-ADM) in adult patients with acute appendicitis and compare its diagnostic performance with conventional inflammatory biomarkers, particularly C-reactive protein (CRP) and the neutrophil-to-lymphocyte ratio (NLR). Acute appendicitis is a common surgical emergency. However, its diagnosis can be challenging because symptoms and laboratory findings are often nonspecific. Although CRP, white blood cell count, and NLR are widely used in clinical practice, their diagnostic accuracy may be limited. Pro-ADM is a biomarker associated with inflammation and infection and may provide additional diagnostic information. The study will prospectively enroll 400 adult participants at Bursa Yuksek Ihtisas Training and Research Hospital, Turkiye. The study population will include patients undergoing appendectomy for acute appendicitis and a control group of individuals without abdominal pain or active inflammatory disease. Demographic characteristics, clinical findings, imaging results, and routine laboratory parameters will be recorded. Blood samples will be collected to determine serum Pro-ADM levels. The diagnostic performance of Pro-ADM will be evaluated using receiver operating characteristic (ROC) curve analysis and compared with conventional inflammatory biomarkers. The study will also investigate the potential value of Pro-ADM in predicting complicated acute appendicitis. The findings may help clarify whether Pro-ADM could serve as an additional biomarker in the diagnostic evaluation of acute appendicitis.

Inclusion Criteria: 1. Adults aged 18 to 90 years. 2. Patients presenting to the emergency department within 48 hours of the onset of abdominal pain, either directly or following referral from another healthcare institution with a diagnosis or suspicion of acute appendicitis. 3. Patients undergoing appendectomy for acute appendicitis (acute appendicitis group). 4. Individuals attending outpatient clinics for routine health evaluations without abdominal pain or active inflammatory disease (control group). 5. Provision of informed consent for participation in the study. Exclusion Criteria: 1. Age younger than 18 years or older than 90 years. 2. Use of antibiotics or systemic corticosteroids within the preceding month. 3. Active malignancy. 4. Immunosuppressive disease or ongoing immunosuppressive treatment. 5. Abdominal surgery within the preceding three months. 6. Heart failure, renal failure, or liver cirrhosis. 7. Pregnancy or postpartum period. 8. Inability to provide informed consent due to psychiatric disorders.