Study of the role of C reactive protein measurement in reducing the rate of negative explorations for acute appendicitis

ABSTRACT

Appendicectomy for suspected acute appendicitis is a common procedure. The rate of normal appendices unnecessarily removed remains high [15-30%] despite several techniques and investigations used to improue our diagnostic accuracy. Many studies investigated the role of raised C-reactive protein in improving the diagnosis of acute appendicitis with con-jlicting results. This study emphasizes the impact of a normal [rather than raised] serum C-reactive protein in reducing the rate of negative explorations. In a double blind study, blood for the measurement of serum C-reactive protein [CRP] was collected pre-operatively from 156 patients just before going to the operating room for appendicectomy. The histopathology of the 156 appendices were grouped into positive [acute appendicitis] and negative [normal appendix]. White blood count [WBC], CRP and the histopathology findings were correlated. In patients with histopathologically proven acute appendicitis both the WBC count and serum CRP level were significantly raised [P=0.025 and P<0.0001 respectively]. Serum CRP level was normal in 26 out of 30 negative explorations [normal appendix on histopathology]. The specificity and sensitivity of serum CRP was 86.6% and 93.6% respectively. A normal preoperative serum CRP measurement in patients with suspected acute appendicitis is most likely associated with a normal appendix Deferring surgery in this group of patients would probably reduce the rate of unnecessary appendicectomies