Background: Acute appendicitis (AA) is the most common surgical emergency worldwide. Its correct and early diagnosis is essential to avoid unnecessary surgeries and complications associated with its natural history. Objective: The aim of this study was to determine the diagnostic sensitivity and specificity of the RIPASA score in patients with suspected AA. Material and methods: This analytical, cross-sectional, observational and retrospective study included appendectomy specimens of patients of both sexes > 18 years operated on with clinical diagnosis of AA between January 1 and December 31, 2017. The histopathological examination of the appendectomy specimens was considered the gold standard diagnostic test. A score of 7.5 for the RIPASA score was chosen as cut-off value. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated. Results: A total of 68 appendectomies were included; 57 (83.82%) specimens were positive for acute appendicitis. Mean age was 43.32 years. The histological diagnosis of AA was present in 32 (84.21%) men and in 25 (83.33%) women. For the RIPASA score, 54 patients had a true positive result (cut-off point ≥ 7.5 and positive histology for AA) with a sensitivity of 93%, specificity of 40%, PPV of 90%, NPV of 50%, positive likelihood ratio of 1.55 and negative likelihood ratio of 0.175. Conclusion: The RIPASA score has demonstrated excellent sensitivity and specificity for the clinical diagnosis of AA in a fast, simple and non-invasive fashion.