Appendicitis is the most common surgical disease evaluated by pediatric surgeons in the emergency department. Despite the history, physical examination, laboratory tests and imaging methods, the misdiagnosis may be observed often in children. Pentraxin-3 (PTX-3) is an acute phase protein which is produced directly in the inflammatory tissue. Our aim was to investigate the diagnostic value of PTX-3 levels in appendicitis in pediatric patients and compare it with the other serum parameters.

Eighty-eight patients (aged <18 years) were included in this study [Group 1 (n = 28) healthy volunteers, Group 2 (n = 28) patients with non-specific abdominal pain, Group 3 (n = 34) patients underwent appendectomy]. Serum white blood cell (WBC), absolute neutrophil count (ANC), neutrophil/lymphocyte ratio (NLR), C-reactive protein (CRP) and PTX-3 values were measured.

Median serum levels of WBC were higher in Group 2 and 3 than Group 1. ANS, NLR, CRP and PTX-3 were higher in Group 2 than Group 1 and were higher in Group 3 than the other groups. The highest sensitivity was found in NLR >3.5 [94.1 (95% CI = 80.3–99.3)] and PTX-3 > 5.6 ng/mL [91.8 (95% CI = 76.3–98.1)]. PTX-3 has the highest specificity among all of the parameters [90.7 (95% CI = 79.7–96.9)]. The area under the ROC curve showed that the diagnostic value of PTX-3 was greater than any other parameter [0.979 (95% CI = 0.92–0.99)].

In this study, we have shown that PTX-3 is very useful with high sensitivity and specificity in the diagnosis of appendicitis compared to WBC, ANS, NLR and CRP as a first in the literature.