Objective: The aim of this study was to evaluate the accuracy of C-reactive protein (CRP) measurements in the diagnosis of suspected acute appendicitis (AA) during childhood.
Patients and methods: A prospective study of 195 consecutive children, aged between 2 and 14 years and suspected of having AA, that attended a pediatric emergency room was carried out. We obtained a careful patient history, physical signs, blood test results, final diagnosis and the histological findings in the cases who underwent appendectomy (classified as normal appendix, simple appendicitis (SA) or gangrenous appendicitis (GA).
Results: The final diagnoses and their frequencies were: AA (94), non-specific abdominal pain (80), mesenteric lymphadenitis (6) and others (15). Appendectomies were performed in 103 cases with 94 cases being AA (91.3%) and of these 51 SA and 43 GA. The average values of CRP (mg/l) were: AA: 30, SA: 16, GA: 67, non-specific abdominal pain: 15, and mesenteric lymphadenitis: 44 (p < 0.01). The values of AG were statistically higher than those of SA (p = 0.0000). The ROC curve of these data determined the best cut-off levels for AA to be 30 (sensitivity: 0.43, specificity: 0.92, predictive value of a positive result: 0.87 and predictive value of a negative result: 0.58).
Conclusions: 1) The value of CRP in AA is higher than in other abdominal pain etiologies. Nevertheless, this value should not be used to deny surgery since it is often normal in SA. 2) When a CRP value > 40 mg/L is found in a suspected AA, one should think about GA and therefore, initiate prophylactic antibiotics and perform surgery immediately.