Aim: Diagnosis of acute appendicitis is a challenging task in children presenting with abdominal pain. We conducted an analytical interpretation of the basic parameters in patients with appendicitis, according to decisive pathologic diagnosis. Material and Methods: We analyzed the clinical files of 12126 patients with abdominal pain and included a sum of 1066 hospitalized patients suggestive of acute abdomen. We accomplished a statistical evaluation of variables as physical examination, symptoms, laboratory findings and ultrasound screening. Results: Histopathological analysis of 657 appendectomies revealed negative appendectomy in 12.3% and complicated appendicitis in 15% (perforated 6.7%). There was no statistical difference in terms of pyrexia and CRP between negative appendectomy and acute appendicitis. WBC count, neutrophil count, and neutrophil lymphocyte rate showed a statistically significant difference (p<0.001) amongst histopathologic groups. ROC analysis revealed AUC (cut-off) values as 0.62 (>= 14500), 0.769 (>= 9.6), 0.689 (>= 4.89) respectively. US revealed 65% sensitivity and 50% specificity rate with 90% of positive predictive value, along with 17% negative predictive value. Secondary findings as presence of peri-appendiceal fluid collection and mesenteric heterogeneity revealed 93.4% and 94.3% sensitivity consecutively. Discussion: We found WBC count, neutrophil count, neutrophil lymphocyte rate, presence of peri-appendiceal fluid and mesenteric heterogeneity in ultrasound screening as highly predictive in differential diagnosis.