Assessment of proadrenomedullin as diagnostic or prognostic biomarker of acute appendicitis in children with acute abdominal pain

Abstract Background Acute appendicitis (AA) is one of the most frequent surgical pathologies in pediatrics. Objectives To investigate the utility of proadrenomedullin (pro-ADM) for the diagnosis of AA. Methods Prospective, analytical, observational, and multicenter study conducted in 6 pediatric emergency departments. Children up to 18 years of age with suspected AA were included. Clinical, epidemiological, and analytical data were collected. Results We studied 285 children with an average age of 9.5 years (95% confidence interval [CI], 9.1–9.9). AA was diagnosed in 103 children (36.1%), with complications in 10 of them (9.7%). The mean concentration of pro-ADM (nmol/L) was higher in children with AA (0.51 nmol/L, SD 0.16) than in children with acute abdominal pain (AAP) of another etiology (0.44 nmol/L, SD 0.14; p p  = 0.005). The areas under the receiver-operating characteristic curves were 0.66 (95% CI, 0.59–0.72) for pro-ADM, 0.70 (95% CI, 0.63–0.76) for C-reactive protein (CRP), 0.84 (95% CI, 0.79–0.89) for neutrophils, and 0.84 (95% CI, 0.79–0.89) for total leukocytes. The most reliable combination to rule out AA was CRP ≤1.25 mg/dL and pro-ADM ≤0.35 nmol/L with a sensitivity of 96% and a negative predictive value of 93%. Conclusion Children with AA presented higher pro-ADM values than children with AAP of other etiologies, especially in cases of complicated AA. The combination of low values of pro-ADM and CRP can help to select children with low risk of AA.