COVID-19 patients often show high-titer non-platelet-activating anti-PF4/heparin IgG antibodies.
Justine BrodardJohanna A Kremer HovingaPierre FontanaJan-Dirk StudtAndreas GreinacherAndreas GreinacherPublished in: Journal of thrombosis and haemostasis : JTH (2021)
COVID-19 patients often present with strong reactivity in PF4/heparin antigen tests without the presence of platelet-activating antibodies. Diagnosis of HIT requires confirmation of heparin-dependent, platelets activating antibodies to avoid overdiagnosis and overtreatment with non-heparin anticoagulants.