Anahtar KelimelerOrtalama Trombosit Hacmi; Cerrahi; Akut Apandisit; Acil Servis Abstract Aim: The diagnosis of acute appendicitis for patients referred to the emergency department with the complaint of abdominal pain remains challenging. In this study, we investigated the diagnostic value of mean platelet volume in acute appendicitis. Material and Method: This clinical research study was performed retrospectively and included patients referred to the emergency department between January 1 and December 31, 2013, with the complaint of abdominal pain and were then discharged without a specific diagnosis in comparison to patients with a proven diagnosis of acute appendicitis. Control patients were selected using a randomization method from among patients of the same age and gender as acute appendicitis patients. The acute appendicitis group was subdivided into complicated and noncomplicated cases according to the pathology results. The Mann-Whitney U test for continuous variables and the chi-square test for categorical data were used. Results: This clinical research study was performed with 316 acute appendicitis patients and an equal number of control patients; 188 of the patients were male. Among the acute appendicitis patients, 67 presented with complicated acute appendicitis and 249 with noncomplicated acute appendicitis. The median mean platelet volume of the acute appendicitis versus control patients was 8.03 fL (IQR: 1.86; min: 5.53, max: 14.40) and 8.10 fL (IQR: 1.38; min: 5.70, max: 13.90), respectively (p=0.193). The platelet counts in the complicated and noncomplicated groups were 235 K/µL (IQR: 70; min: 116, max: 649) and 261 K/µL (IQR: 87; min: 124, max: 537), respectively (p<0.001). Discussion: Mean platelet volume is not a useful guide in the diagnosis of acute appendicitis for patients referred to the emergency department with the complaint of abdominal pain.