The diagnostic value of C-reactive protein and white blood cell count in diagnosis of acute appendicitis

Abstract

Introduction Appendectomy is one of the commonest operations performed annually. Despite the advancement in the laboratory tests and radiological tests, still the rate of negative appendectomies is 15-30%. This study was designed to assess the diagnostic value of quantitative C-reactive protein (CRP) and white blood cell count (WCC) in patients suspected to have acute appendicitis. Patients and methods Our study is a prospective study that was conducted between December 2012 and March 2013 after approval of the ethical committee. Inclusion criteria Patients with clinically diagnosed acute appendicitis without generalized peritonitis. Exclusion criteria Patients with generalized peritonitis All patients were subjected to the following Clinical examination Routine bloods immediately after decision to admit including full blood count and CRP. Urine test Pregnancy test for all females Ultra sound scan to rule out other causes of abdominal pain All the patients were operated upon via open approach and the appendix was sent for histopathological analysis and the results were compared with C-Reactive protein (CRP) and the WBC (White blood cell count) and the results were compared using t-tests. Results Our study recruited 100 patients, 60 males (60%) and 40 females (40%), in the age range 20-55 years. The histopathological analysis showed acute appendicitis in 85 patients (85%), the operative notes showed 60 patients with noncomplicated appendicitis, 25 patients with complicated appendicitis; the WCC alone has a sensitivity of 85%, specificity of 75%, CRP alone has a sensitivity of 93.3% and specificity of 86.6%, WCC alone had positive predictive value of 44% and it improves to 70% when both parameters are combined together, whereas the negative predictive value of the WCC was 100%. In patients with normal appendix the mean CRP level was 10.6 mg/l, the median level was 10.6 mg/l, and the mean WCC was 8 Χ 10 9 cells/l, the median WCC 7 Χ 10 9 cells/l, whereas in patients with noncomplicated acute appendicitis (n = 60) the mean CRP was 40 mg/l, the median was 20 mg/l; in patients with complicated appendicitis (n = 25) the mean CRP was 90 mg/l and the median was CRP 60 mg/l. Conclusion We suggest that patients experiencing lower abdominal pain, with normal CRP values and normal WCC are unlikely to have acute appendicitis and need further investigations before embarking onto surgery.