Combined Diagnostic Accuracy of Total Leukocyte Count, Neutrophil Count, and Ultrasonography for the Diagnosis of Acute Appendicitis

Acute appendicitis is a common surgical emergency that classically presents with right lower abdominal pain and tenderness on palpation. The diagnosis is often based on clinical examination in order to avoid the complications of surgery delay, yielding a high rate of negative appendectomies. Ultrasonography is a regularly used modality for establishing the diagnosis, whereas abdominal computed tomography (CT) is often used in sonologically equivocal cases. Other parameters include total leukocyte count, granulocytes, C-reactive protein (CRP), leukocyte elastase activity, D-lactate, phospholipase A2, and interleukin-6 (IL-6). We conducted a prospective study to assess the combined accuracy of total leukocyte count, neutrophil count, and ultrasound as an integrated diagnostic tool. The results of these investigations were tabulated and compared to histopathological evidence of acute appendicitis on biopsy (taken as the gold standard) to calculate sensitivity, specificity, positive predictive value, and negative predictive value. Combined sensitivity and specificity were calculated using cross-tabulation, whereas diagnostic accuracy was estimated from the receiver operating curve (ROC) at the optimal cut-off point. The results showed that the absence of inflammatory findings on ultrasound and normal blood parameters (total leukocyte count and neutrophil count) have a high combined diagnostic accuracy and appendicitis may be ruled out.