Pseudothrombocytopenia with cold-type platelet agglutinins.

Pseudothrombocytopenia is an in vitro phenomenon of platelet agglutination and clumping in the presence of EDTA on the electronical measurement of platelet count. Agglutinins reacting with platelet antigens belong to one heavy and one light chain of immunoglobulins with or without complement by immunofluorescence. The platelets are markedly agglutinated in EDTA, but scarcely in the presence of other anticoagulants. Agglutinations seem to occur more readily at cold temperature rather than at 37 degrees C.