<p>Immune thrombocytopenia (ITP) is marked by decreased platelet counts and an increased bleeding risk, while functional platelet exhaustion may also underlie its clinical variability. This study investigates whether platelet functional competence can help differentiate “responder” (R) from “non-responder” (NR) ITP patients. Platelets obtained from 28 chronic ITP patients and 20 healthy controls, either in resting condition or in the presence of PMA, were subjected to flow cytometry, where the levels of platelet activation markers (P-selectin expression, PAC-1 binding) and reactive oxygen species (ROS) were assessed. In ITP, baseline levels of P-selectin and PAC-1 were higher compared to healthy controls, while their levels in response to PMA were significantly lower (p˂0.05). Baseline ROS also showed a significant difference between ITP and controls, and ROS generation in response to PMA was reduced in ITP compared to controls (p˂0.05). “NR” exhibited elevated basal P-selectin and diminished PMA-induced activation while bleeding scores showed no correlation with basal P-selectin. ROC curve analysis and multiple logistic regression models identified PMA-induced ROS and P-selectin responses as strong predictors of bleeding severity and treatment response in ITP. Panel analysis, including platelet activation markers and ROS generation in response to PMA, successfully distinguished the disease status with an adjusted AUC of 92 (95%CI:80.7–100), an optimum cut-off value of 0.228, sensitivity of 87.5%, and specificity of 85.0%. A novel composite index of platelet functional analysis was developed to overcome limitations of conventional assessment of ITP status. This multifactor panel accurately reflects platelet functional state while helping to distinguish between responder and non-responder patients. The panel could offer a promising tool for improved diagnosis, prognosis, and individualized patient management.</p>