BackgroundEven today, the diagnosis of acute appendicitis (AA) is still problematic. Here, we offer a new palpation sign for the diagnosis of AA. In this study, we evaluate the efficacy of the sign for the diagnosis of atypical forms of AA (i.e., in children and women of childbearing age).MethodsWe have retrospectively analysed 2245 patients - children (aged 0–12), men (aged 12–18) and women of childbearing age (aged 12–45) with suspected AA, 401 of whom underwent surgery. Patients were divided into one of three age categories and, based on clinical data and histological findings, were defined as either false negative, false positive, or positive. Confirmed positive AA was defined based on histological findings, and confirmed negative AA was defined by histological findings as well as on clinical follow-up. Pearson’s correlation analysis was used for the assessment of the correlation between the patient’s gender, age as well as their clinical and histological findings.ResultsBased on these statistical results, we came to the following results. In children (aged 0–12, male/female) and in women of childbearing age (aged 12–45), we observed 14 (3,46%) false negative clinical findings for the palpation sign. In children and women of childbearing age, we observed a higher percentage of palpation sign positivity compared to false positivity. The new palpation sign minimizes unindicated revisions of the abdominal cavity, serves as a reliable indicator for surgery and is suitable for the diagnosis of AA in atypical forms (i.e., in children and women of childbearing age) with a sensitivity of 95,57%, a specificity of 95,78%, a positive predictive value of 67,86%, a negative predictive value of 99,50%, a positive likelihood ratio of 24,28, a negative likelihood ratio of 0,05 and an accuracy of 95,9%. The negative appendectomy rate in women of childbearing age was 9.22% and in children 6,72%.ConclusionWe conclude that the new palpation sign is effective (r > 0.95) for the diagnosis of atypical forms of AA (i.e., in children and women of childbearing age). It is aimed principally at the medical practitioners in different parts of the world and in a state of emergency (Covid-19 pandemic, wars, etc.) where the diagnostic facilities and technological resources are limited.