Role of mean platelet volume in differential diagnosis of adult-onset Still's disease and sepsis

OBJECTIVES: Mean platelet volume is a simple biomarker for inflammatory disease. The purpose of this study is to evaluate the role of mean platelet volume in distinguishing adult-onset Still's disease from sepsis. METHODS: We retrospectively selected 68 patients with adult-onset Still's disease and 55 patients with sepsis between January 2015 and December 2019. Related laboratory data were collected and analyzed. RESULTS: There were no significant differences in white blood cell counts, neutrophils, lymphocytes, and C-reactive protein between adult-onset Still's disease group and sepsis group. However, patients in adult-onset Still's disease group showed higher ferritin and platelets and lower mean platelet volume and platelet distribution width than those in sepsis group (p<0.01 for both). Receiver operating characteristic curve analysis was performed to distinguish adult-onset Still's disease and sepsis. The area under the curve of mean platelet volume was 0.761 (95%CI 0.673-0.849), with a sensitivity of 79.1%, a specificity of 63.3%, and a cutoff value of 10.9 fL. In contrast, the area under the curve of combined ferritin and mean platelet volume was 0.90l (95%CI 0.837-0.965), with higher sensitivity (82.8%) and specificity (96.2%). Therefore, mean platelet volume could be used as a supplementary indicator to distinguish adult-onset Still's disease from sepsis. CONCLUSION: We suggest that mean platelet volume could be used as a supplementary biomarker for differential diagnosis of adult onset Still's disease and sepsis in addition to ferritin.