On multivariate analysis, patients with AA were four times more likely to have an elevated neutrophil count above 7 × 109/L on admission and three times more likely to have an elevated CRP above 5 mg/L on admission compared to patients who did not have appendicitis (Table 3). A radiological diagnosis of AA by either modality had an odds ratio of 8.0 for a histological diagnosis of AA (P < 0.001). This evidence concerns the gene CRP and appendicitis.