Diagnostic values of a single serum biomarker at different time points compared with Alvarado score and imaging examinations in pediatric appendicitis.

Background: A large number of children with right lower quadrant pain are evaluated on a daily basis by primary care clinicians in order to rule out acute appendicitis. The aim of this study was to determine the cutoff values of serum biomarkers, including white blood cell (WBC) count and C-reactive protein (CRP) in predicting pediatric appendicitis based on how long the patients' symptoms were present. We further compared the diagnostic values of these serum biomarkers with the Alvarado score and imaging examinations.

Materials And Methods: This prospective study comprised of 594 pediatric patients with suspected appendicitis was conducted at a medical center in Taiwan from 2004 to 2006. Receiver operating characteristic (ROC) curves were used to establish the best cutoff values of serum biomarkers for discriminating pediatric appendicitis. We further analyzed the diagnostic values of the Alvarado score, abdominopelvic computerized tomography (CT), and ultrasonography in predicting appendicitis, and then compared them with our selected serum biomarkers.

Results: ROC analysis showed that the best cutoff value of WBC count was 11,000/mm on the first day after onset of symptoms (d 1), and the best cutoff values of CRP concentration were 25 mg/L (d 2) and 89 mg/L (d 3) in diagnosing acute appendicitis. The cutoff values of CRP concentration to indicate perforated appendicitis were 24 mg/L (d 1), 50 mg/L (d 2), and 119 mg/L (d 3). A single serum biomarker at different time points has a diagnostic value, which is as favorable as that of Alvarado score and CT imaging and better than that of ultrasonography in predicting pediatric acute or perforated appendicitis.

Conclusion: A single serum biomarker at different time points has a favorable diagnostic value, which is inexpensive, objective, and readily available without the risk of radiation or the need of sedation and is useful for primary caregiver.