RÉSUMÉ
OBJECTIVE: Adult appendicitis (AA) with equivocal computed tomography (CT) findings remains a diagnostic challenge for physicians. Herein we evaluated the diagnostic performance of several clinical scoring systems in adult patients with suspected appendicitis and equivocal CT findings. METHODS: We retrospectively evaluated 189 adult patients with equivocal CT findings. Alvarado, Eskelinen, appendicitis inflammatory response, Raja Isteri Pengiran Anak Saleha Appendicitis (RIPASA), and adult appendicitis score (AAS) scores were evaluated, receiver operating characteristic analysis was conducted, and the optimal, low, and high cut-off values were determined for patient classification into three groups: low, intermediate, or high. RESULTS: In total, 61 patients were included in the appendicitis group and 128 in the non-appendicitis group. There were no significant differences between the area under the curve of the clinical scoring systems in the final diagnosis of AA for equivocal appendicitis on CT (Alvarado, 0.698; Eskelinen, 0.710; appendicitis inflammatory response, 0.668; RIPASA, 0.653; AAS, 0.726). A RIPASA score greater than 7.5 had a high positive predictive value (90.9) and an AAS score less than or equal to 5 had a high negative predictive value (91.7) in the diagnosis of AA. CONCLUSION: The accuracy of clinical scoring systems in the diagnosis of AA with equivocal CT findings was moderate. Therefore, a high RIPASA score may assist in the diagnosis of AA in patients with equivocal CT findings, and a low AAS score may be used as a criterion for patient discharge. Most patients presented with intermediate scores. The patients with equivocal CT findings may be considered as a third diagnostic category of AA.