Prospective evaluation of diagnostic modalities in suspected acute appendicitis

The aim of this prospective study was to evaluate different diagnostic modalities routinely employed in a district hospital.

Four hundred subsequent patients presenting with acute abdominal pain were included over a period of 18 months. Patient characteristics, diagnostic work-up, intraoperative findings, histology and clinical outcome were documented. Rectal temperature, white cell count (WCC), C-reactive protein (CRP), ultrasonography (US) and Ohmann score were analysed with relation to diagnostic value.

Negative appendicectomy rate and negative laparotomy rate on the day of admission were 22% and 21%, respectively. Sensitivity was highest for WCC and CRP (0.82 and 0.85) but US showed highest values for specificity (0.92), accuracy (0.85) and odds ratio (13.06). No patient with an Ohmann score below 6.5 suffered from acute appendicitis. With regard to different levels of training in US, experienced surgeons and radiologists had best values for specificity (1.00 and 0.98) and accuracy (0.90 and 0.94). Surprisingly, less-experienced sonographers also achieved good results with regard to specificity (up to 0.96) and positive predictive value (up to 0.89).

Diagnostic accuracy of acute appendicitis remains insufficient, with an unacceptable high rate of unnecessary operations. Only the promotion of routine ultrasonography might contribute to an improvement in the near future.