Abstract: A method for the detection of heparin-dependent antibodies and the diagnosis of immune or autoimmune pathologies potentiated by a heparin substance, such as thrombocytopenia induced by heparin (HIT type II) as inducer drug. The method includes the steps of reacting at least one substance with high affinity for a heparin substance (SFA), with at least one heparin substance (SH) so as to form a substance with high affinity for heparin-heparin substance (SFA-SH) complex. The heparin substance is adapted to bind other substances with affinity for heparin and with at least one potential antigenic substance capable of reacting with the heparin substance, forming a (Ag-SH) complex. The method further includes the steps of testing a patient's plasma or serum potentially containing an anti(Ag-SH) antibody after administration of the heparin substance and revealing the resulting (Ag-SH)-anti(Ag-SH) complex produced.