Platelet Indices as Diagnostic Marker for Kawasaki Disease.

Various candidate biomarkers have been investigated for the early and accurate diagnosis of Kawasaki disease (KD). We aimed to evaluate platelet activity using platelet indices (PI) in patients with KD or simple febrile illness to determine whether these indices might support a diagnosis of KD. Another objective of the study was to delineate the changes in PI from the acute to convalescent phases of KD. A total of 225 patients with complete KD (cKD), 110 with incomplete KD (iKD), and 71 with simple febrile illness (control) were enrolled. PI included mean platelet volume (MPV), platelet distribution width (PDW), and plateletcrit (PCT). We serially measured the serum PI four times for each patient with KD from the acute to convalescent phases: on D0 (day of intravenous immunoglobulin (IVIG) treatment) and repeated on days 2 (D2), 14 (D14), and 56 (D56) after IVIG therapy. Data from the control group were collected during the acute stage of the disease (D0). The platelet counts in the cKD (341±103×10³/mm³) and iKD (374±135×10³/mm³) at diagnosis were higher than the control group (290±128×10³/mm³). The PCT in the cKD (0.284±0.085%) and iKD (0.313±0.109%) groups at diagnosis were also higher than the control group (0.246±0.108%). However, the MPV and PDW levels in the KD group were not statistically significant. Therefore, platelet count and PCT are adjuvant parameters for the differential diagnosis of KD from a simple febrile illness.