WBC Count vs. CRP Level in Laboratory Markers and USG vs. CT Abdomen in Imaging Modalities: A Retrospective Study in the United Arab Emirates to Determine Which Are the Better Diagnostic Tools for Acute Appendicitis

Abstract

Introduction Acute Appendicitis (AA) is the most common surgical emergency. Despite the use of various diagnostic parameters, the rate of negative appendectomy remains high (30%). Thus, through our retrospective study, we aim to analyse whether white blood cell (WBC) count or C-reactive protein (CRP) level is more indicative in the confirmation of AA. We also analysed imaging modalities ultrasonography (USG) and computed tomography (CT) of the abdomen to find out which is better for diagnosing AA. Methods Patients with suspected AA admitted for laparoscopic appendectomy in Saqr Hospital, Ras Al Khaimah, United Arab Emirates, during 2019-2020 were included in the study. Patients who had either or both WBC and CRP values were included in the study and their diagnosis was confirmed based on histological appendectomy findings. Data analysis was done using IBM SPSS Statistics for Windows, Version 23.0 (Released 2015; IBM Corp., Armonk, New York, United States), receiver operating characteristic (ROC) curve, and chi-square test as required. p-value of <0.05 was considered statistically significant. Results Out of the 320 patients with suspected AA, WBC had a p-value of 0.8 (insignificant). A total of 228 patients who had elevated WBC had confirmed histological diagnosis of AA, and 152 patients who were tested for CRP and had elevated levels had confirmed histological diagnosis of AA. CRP had a p-value of 0.04 (significant). However, when the ROC curve was used as evidence to see which was a better test, WBC and CRP both had a low area under the curve (AUC), which proved that they were not the most accurate diagnostic marker in diagnosing AA. However, CRP was slightly better than WBC. A total of 266 patients underwent USG abdomen and it had a p-value of 0.4 (insignificant), while 118 patients underwent CT scan, which had a p-value of 0.01 (significant). CT abdomen was statistically proven as a better radiological investigation. Also, when the ROC curve was used to compare USG and CT abdomen, CT again proved to be a better radio diagnostic method for AA. Conclusions From our study, it can be concluded that CRP is better than WBC in ruling in appendicitis and CT abdomen is better than USG in diagnosing appendicitis, but CT abdomen is only next to histological diagnosis in confirming AA. Hence, we recommend doing CRP as the primary laboratory marker for suspected cases of AA. CT abdomen is the ideal imaging modality in cases of suspected AA where clinical examination, laboratory values, and ultrasound examination are inconclusive.