PF4 and Thrombocytopenia: Thrombocytopenia (platelet count 42 × 109/L), elevated d‐dimer level ( > 10,000 FEU ng/mL), and positive anti‐PF4 IgG antibody ELISA tests [658.3 ng/mL (normal, 42.1–313.4 ng/mL)