THE DIAGNOSTIC VALUE AND NATURAL HISTORY OF C-REACTIVE PROTEIN IN PATIENTS OPERATED ON FOR PRESUMED DIAGNOSIS OF ACUTE APPENDICITIS

Abstract

To evaluate the predictive value of C-reactive protein (CRP) in patients operated on for presumed diagnosis of acute appendicitis, CRP levels at preoperative period and 24, 48 and 72 hours postoperatively were detected quantitatively in 143 consecutive patients who underwent appendectomy between September 1999 and July 2001. The surgeon was blinded of their results. The sensitivity and specifity of CRP as well as its optimal cut-off value for both were investigated comparing with leukocyte levels. The difference between groups and their postoperative CRP kinetics were evaluated. Histo-pathological findings confirmed an inflamed appendicitis in 95 patients, pertorated appendicitis in 22 patients, lymphoid hyperplasia or normal appendix in remaining 26 patients, 10 of which had other surgical pathologies. In all patients with perforated appendicitis, serum CRP levels were elevated while 9 patients with inflamed appendicitis have a normal CRP levels. The number of patients with normal CRP levels were significantly fewer than those with normal WBC in nonappendicitis groups (8/26 vs 15/26; p<0.05). The sensitivity, specifity, positive, and negative predictive value of preoperative CRP levels were respectively 92.3%, 69.2%, 93.1, %, 66.7% with an accuracy of 88. 1 %. The cut-off value of CRP for optimal sensitivity and specifity was found to be 20.2 mg/L by a 'Receiver Operating Characteristics' curve. While other surgical pathology and nonspecific abdominal pain groups showed similar patterns(p=0.097), postoperative CRP kinetics were different between appendicitis groups and the other groups(p<0.01). Serum CRP levels greater than 20 mg/L may support the surgeon's clinical diagnosis while the normal CRP levels may be used for further observation of the patient when the diagnosis is obscure. Postoperative CRP kinetics in acute appendicitis differ from other medical or surgical diseases causing right iliac fossa pain.