Heparin-induced thrombocytopenia: use of indirect immunofluorescence

Sera from 14 patients who developed heparin-induced thrombocytopenia were tested by an indirect platelet immunofluorescent test in an attempt to characterize the serologic reactions between platelets, heparin, and the antibody. Positive results were observed in seven cases with variable patterns of reactions in the tests when performed in the presence or the absence of the offending drug. It was possible to absorb out the antibody in the presence of heparin and recover the antibody in the eluate. Neither complement nor the presence of immune complexes were found to play a role in the thrombocytopenia induced by heparin.