
Diagnostic Sensitivity of CT Scan, Ultrasonography, and CRP Alone and in Combination for Appendicitis
Majid Zamani 1 ℗, Fatemeh Ghorbani 2, Fatemeh Ansari 3, Erfan Erfanian 3, Fatemeh Pouladkhay 4 ©
Abstract
Introduction: Acute appendicitis represents one of the most common and clinically significant causes of emergency hospital admissions. Failure to establish an accurate diagnosis may lead to severe complications, including intestinal perforation and potentially fatal outcomes. Consequently, the implementation of reliable diagnostic modalities is critically important. This study aimed to assess the diagnostic sensitivity of computed tomography (CT) scans, ultrasonography, and C-reactive protein (CRP) levels, both individually and in combination, in appendicitis. Methods and Materials: This retrospective study was conducted with ethical approval (IR.GMU.REC.1403.140) from Gonabad University of Medical Sciences. Medical records of 147 patients who underwent appendectomy at Bohlool Gonabadi Hospital between February 2022 and April 2025 were reviewed. Exclusion criteria included a history of malignancy, pregnancy, or substance/smoking addiction. Collected data comprised age, sex, ultrasonography and CT scan findings, CRP levels, leukocyte and neutrophil count, and clinical symptoms (pain, nausea, fever, and tenderness). Data are presented as mean ± standard deviation (SD) and percent. Statistical analyses were conducted using SPSS version 27. Results: Medical records were from 81 (55.1%) male and 66 (44.9%) female with a mean age of 26 ± 17.2 years. CT scans were positive in 115 cases (78.2%) and negative in 32 cases (21.8%), whereas ultrasonography was positive in 129 cases (87.8%) and negative in 18 cases (12.2%). CRP testing yielded 94 positives (63.9%) and 53 negatives (36.1%). The sensitivity of CT scan, ultrasonography, and CRP was 78.2%, 87.8%, and 63.9%, respectively. Combined sensitivity were 52.4% for CRP + CT scan, 58.5% for CRP + ultrasonography, 76.9% for CT scan + ultrasonography, and 51.0% when all three tests were combined. Conclusion and Discussion: Ultrasonography demonstrated the highest sensitivity among the diagnostic tests evaluated. This study revealed a reduction in sensitivity when tests were combined. However, utilizing multiple diagnostic modalities for appendicitis identification may help reduce unnecessary surgeries. While this study provides valuable insights into the sensitivity of individual and combined tests, certain limitations must be acknowledged. The relatively small sample size, absence of hematological and clinical data, lack of normal appendix controls, and inability to calculate specificity, positive predictive value (PPV), and negative predictive value (NPV) may affect the generalizability of these findings and should be addressed in future research.
Keywords: Appendicitis, ultrasonography, computed tomography, C-reactive protein