Used in clinical and research laboratories to measure platelet factor 4 (PF4) levels in human biological samples such as plasma or serum. It is particularly valuable in diagnosing and monitoring heparin-induced thrombocytopenia (HIT), a serious immune-mediated adverse reaction to heparin therapy. The kit enables sensitive and specific detection of PF4 released from platelets, aiding in the assessment of platelet activation and thrombotic risk. It is also used in studies of inflammation, thrombosis, and immune responses involving chemokine signaling. The assay supports quantitative analysis, making it suitable for longitudinal studies and evaluation of therapeutic interventions.