Diagnostic accuracy of fibrinogen to differentiate appendicitis from nonspecific abdominal pain in children

The aim of this study was to assess the diagnostic accuracy of the biomarker fibrinogen (FB), along with the more traditional markers white blood cell count (WBC), absolute neutrophil count (ANC), and C-reactive protein (CRP), to discriminate appendicitis from nonspecific abdominal pain (NSAP) in children. We prospectively evaluated all children aged 5 to 15 years admitted for suspected appendicitis at an academic pediatric emergency department during 2 years. Diagnostic accuracy of FB (prothrombin time–derived method), WBC, ANC, and CRP was assessed by the area under the curve (AUC) of the receiver operating characteristic curve. A total of 275 patients were enrolled in the study (143 NSAP, 100 uncomplicated appendicitis, and 32 complicated appendicitis). WBC and ANC had a moderate diagnostic accuracy for appendicitis vs NSAP (WBC: AUC 0.79, ANC: AUC 0.79). FB and CPR had a poor diagnostic accuracy for appendicitis vs NSAP (FB: AUC 0.63, CRP: AUC 0.64) and a good diagnostic accuracy for complicated vs uncomplicated appendicitis (FB: AUC 0.86, CRP: AUC 0.90). All inflammatory markers had a good diagnostic accuracy for complicated appendicitis vs NSAP. WBC and ANC are useful inflammatory markers to discriminate appendicitis from NSAP. FB and CRP are not very useful to discriminate appendicitis from NSAP, but they discriminate properly complicated from uncomplicated appendicitis and NSAP, with a similar diagnostic accuracy. In a child with suspected appendicitis, a plasma FB level (prothrombin time–derived method) >520 mg/dL is associated to an increased likelihood of complicated appendicitis.