“…Two studies, one retrospective and the second prospective, of US evaluation specifically of patients with atypical presentation of appendicitis, atypical lab results [59], or nonspecific abdominal pain [60] were identified in the current literature. The first demonstrated US sensitivity, specificity, PPV, NPV, and accuracy of 71.4%, 78.5%, 94.8%, 33.3%, and 72.5%, respectively.…”