PF4 and Venous thrombosis: The time course for spontaneous HIT‐like syndromes typically involves a rapid onset of thrombocytopenia and thrombosis without prior heparin exposure, followed by persistent PF4 antibody‐mediated platelet activation for several weeks, with antibody levels usually declining within 2–4 weeks, coinciding with platelet count recovery, although the exact duration can vary between patients and may be influenced by treatment.14