Usefulness of New and Traditional Serum Biomarkers in Children With Suspected Appendicitis

Abstract Objective To evaluate the usefulness of the leukocyte (WBC) and neutrophil (ANC) counts, the values of C-reactive protein (CRP), procalcitonin (PCT) and calprotectin (CP) and the APPY1 Test panel of biomarkers, to identify children with abdominal pain at low risk of appendicitis. Method Children 2-14 years of age with abdominal pain suggesting AA were prospectively included. PCT, CP, CRP, WBC, ANC and the new plasma APPY1 Test were performed. The final diagnosis was determined by histopathology in cases of AA and telephone follow-up in children discharged without AA. Results Between February 2012 and June 2013, 185 children were enrolled with an average age of 9.32 ± 2.7 years. Eighty-nine (48.1%) were finally diagnosed with AA. The APPY1 Test panel showed the highest discriminatory power, sensitivity 97.8 (95% CI 92.2 to 99.4), negative predictive value (NPV) 95.1 (95% CI 83.9 to 98.7), negative likelihood ratio (LR) 0.06 (95% CI 0.01 to 0.22) and specificity 40.6 (95% CI 31.3 to 50.5). A negative APPY1Test and ANC < 7500/ml, provided a sensitivity of 100 (95% CI 95.9 to 100), NPV 100 (95% CI 89.8 to 100) and specificity 35.4 (95% CI 26.6 to 45.4). In the multivariate analysis, only the APPY1Test and ANC > 7500/ml, were significant risk factors for AA (OR 13.76, 95% CI 3.02 to 62.57 and OR 6.37, 95% 2.89 to 14.28, respectively). Conclusions The APPY1 Test panel with ANC could be useful in identifying children with abdominal pain suggestive of AA who are at low risk of this disease.