PF4 and Thrombocytopenia: The positivity rate of the serum anti-PF4/heparin antibody was not significantly correlated with age, sex, body weight, BMI, SBP, DBP, hemoglobin, platelet count and thrombocytopenia, serum creatinine, albumin, bleeding events within the past three months, thromboembolic events within the past three months, the dialysis duration in months, the number of weekly dialyses, dialysis membrane, dialyzer, anticoagulant, and Kt/v (Table 3).