Summary Heparin-induced thrombocytopenia (HIT) has immunospecific genesis and is associated with increased risk of fatal thrombosis (about 90%). The symptoms and treatment of HIT are now known, but most hospitals are not yet available for its specific immunodiagnostics. Laboratory databaseof multidisciplinary hospitalin 2013-2014 (540 beds, 49439 treated patients) revealed3256 blood samples with severe thrombocytopenia (<100×10 9/dl) obtained from 742 patients (1,5% of the total number of hospitalized). Heparins are obtained in 350 of them (47,2%). Thus, the number of patients with HIT may reach 175 annually. Frequency rating of HIT occurrence in the hospital departments: cardio surgery>cardiology>neurological>oncological>traumatology>vascular>surgery>urology> therapy. The first HIT-laboratory center inSt. Petersburginthe ClinicalHospital№122isabletoprovidetheneedsofurban hospitals.