Accuracy of Mean Platelet Volume (MPV) and Red Cell Distribution Width (RDW) for the Diagnosis of Acute Appendicitis: Evaluation of Possible New Biomarkers

INTRODUCTION: Acute appendicitis is the most common cause of the abdominal pain in surgery. Despite its significant prevalence, the diagnosis is associated with many problems in some cases, which leads to false appendectomy. OBJECTIVE: The aim of this study was to determine the validity of diagnostic tests of mean platelet volume (MPV) and red cell distribution width (RDW), as a new possible tool in the diagnosis of acute appendicitis. Methods: In this study, all patients who referred to the emergency department of Besat Hospital, Hamadan, Iran, in 2015, with abdominal pain and first impression of acute appendicitis, undergone appendectomy, were evaluated. The diagnostic markers of pre-operative and post-operative pathology and the validity of MPV and RDW were determined in diagnosis of acute appendicitis. RESULTS: Laboratory and clinical data from 438 patients, presenting the signs and symptoms of acute appendicitis with the mean age of 26.51±13.9 years, were examined (55.6% men). The sensitivity, specificity, positive and negative predictive value of MPV in the diagnosis of acute appendicitis were 59.77, 98.66, 99.5 and 34.26 percent, and for the RDW were 57.79, 56.00, 86.07 and 21.98 percent, respectively. The area under the receiver operating characteristic (ROC) curve for RDW and MPV was 0.61and 0.90, respectively. The mean of MPV in patients with normal pathologic outcome was 9.52±1.60 and in patients with acute appendicitis was 7.51±1.22. There was a significant difference between the mean MPV in both groups (p<0.001). The mean of RDW in patients with normal pathology were 13.42±1.97 and 13.05±1.09, in patients with acute appendicitis. There was a significant difference between the mean RDW of the two groups (p=0.009). CONCLUSION: MPV and RDW indexes have the potential to be used by the surgeons in diagnosis of acute and perforated appendicitis, especially in adults, in order to reduce unnecessary appendectomy, but MPV is more valid in screening acute appendicitis, compared to the RDW.