The diagnosis and management of heparin‐induced thrombocytopenia in Japan

Heparin-induced thrombocytopenia (HIT) is one of the most important complications of heparin, and results in thrombosis despite its use as an anticoagulation therapy. Although the clinical information is helpful, laboratory tests are essential for diagnosing HIT; two principles of assays detecting anti-PF4/heparin antibody (HIT Ab) exist, i.e., an immunoassay and a functional assay. 14C serotonin release assay (14C-SRA), a representative functional HIT Ab assay, is established to be a golden standard test for HIT, the usage of radioisotope hampers its wide spread, especially in Japan. Although immunological HIT Ab can be assayed by commercially available kits, whether this HIT Ab activates platelets cannot be assessed by this method. Recently in Japan, the automated immunoassay for HIT Ab detection has been approved as a clinical laboratory test in the national medical insurance system; only the latex agglutination test is now widely used clinically because of its simplicity, convenience and cost-effectiveness. In this review, we describe the present status of the diagnosis and management of patients with suspected HIT in Japan.