Diagnostic performance of routine platelet indices and novel hemogram-derived composite biomarkers in adult sepsis

Aim Sepsis is a serious infectious condition that can lead to multiple organ failure and can be fatal if not diagnosed and treated early. Although many parameters have been evaluated in the early diagnosis of sepsis, platelet-related factors have been studied to a limited extent. The aim of this study was to evaluate conventional platelet indices and explore the diagnostic performance of hemogram-derived composite indices, including WBC × PDW, in adult sepsis. Methods This retrospective study included 101 patients diagnosed with sepsis according to the Sepsis-3 criteria and 100 healthy control patients between 1 July 2023 and 31 December 2023. Laboratory parameters thought to be associated with inflammation were compared between the groups. Results In the sepsis group, a significant increase in white blood cell (WBC) and neutrophil counts was observed compared to the control group, while hemoglobin, lymphocyte count, platelet count (PLT), and plateletcrit (PCT) values decreased significantly. Mean platelet volume (MPV) and platelet distribution width (PDW) values were found to be significantly higher in sepsis group. Furthermore, PDW showed the strongest correlation with procalcitonin and inflammatory parameters. According to the ROC analysis, in the evaluation of the diagnostic performance of conventional platelet indices (such as MPV and PDW) and combined ratios (such as MPV/PLT and PDW/PLT), the WBC × PDW index demonstrated the strongest discriminatory value (AUC = 0.815). Conclusion While platelet counts decreased in patients with sepsis, MPV and PDW values increased significantly. New composite and ratio indices derived from the complete blood count [MPV/PLT [AUC = 0.712], PDW/PLT [AUC = 0.748], and the WBC × PDW index [AUC = 0.815]] demonstrated superior diagnostic performance in distinguishing sepsis from healthy controls.