Introduction: Acute appendicitis is one of the most common surgical emergencies, with a lifetime prevalence
rate of approximately one in seven. A negative appendicectomy is taken as a surgery performed for a preoperative
diagnosis of appendicitis that results in a normal histopathology specimen. Different techniques have been devised
to assist in equivocal cases in attempts to decrease negative appendicectomy rates.
Aim of work: To compare the diagnostic accuracy of pelviabdominal computed tomography with oral and
intravenous contrast versus appendicitis inflammatory response score in the diagnosis of acute appendicitis.
Patients and methods: This is a cross-sectional study conducted at (The General Surgery Department), Ain
Shams University Hospitals between Jan 2023 and June 2023. 64 patients underwent appendectomy based on
the decision of the consultant after clinical examinations and investigations including pelviabdominal computed
tomography with oral and intravenous contrast. The accuracy of the pelviabdominal computed tomography was
compared with the appendicitis inflammatory response score. The evaluation was based on the Histopathology
postoperatively in Standardized Pathology laboratory in Ain Shams University Hospital.
Results: Histopathology among the studied patients was found positive in 60 cases (93.8%) negative 4 cases
(6.2%). Receiver operating characteristic curve (ROC) showed that the best cut off point of (AIR) score to detect
positive cases according to histopathology was ≥5 with sensitivity of 85.00%, specificity of 75.00%, PPV of 98.1%,
NPV of 25.0% and total accuracy of 84.4.0%. CT scan sensitivity of 98.33%, specificity of 100.00%, PPV of
100.0%, NPV of 80.0% and total accuracy of 99.2%. P vale was 0.041 when the cut off value of AIR score was
equal or more than 5 in comparison to CT scan.
Conclusion: To conclude, this study validates that the Appendicitis Inflammatory Response score has high
discriminating powers and diagnostic accuracy they could aid in selecting patients who require timely surgery or
those who require further evaluation. The high probability score can be conclusive without use of CT scan, within
intermediate and low probability CT scan could add diagnostic value and decrease negative appendectomies. In
case of unavailability of CT scan AIR score can be used with cut off value equal or more 5 with high diagnostic
accuracy and sensitivity.