This observational study aims to evaluate the diagnostic value and clinical utility of detecting the KIT-D816V mutation in the peripheral blood of adult patients with systemic mastocytosis (SM), using droplet digital PCR (ddPCR). Currently, the diagnosis of SM relies heavily on invasive bone marrow biopsies. This study will determine whether highly sensitive ddPCR testing of peripheral blood could provide a reliable, minimally invasive alternative for detecting the KIT-D816V mutation, which is a key driver of the disease and a major diagnostic criterion. The results could optimize the diagnostic process and continuous monitoring of adult SM patients.