Efficiency Of Diagnosing Hit At A Large Academic Medical Center

Background: Thrombocytopenia during heparin administration is common in hospitalized patients, leading to frequent testing for heparin-induced thrombocytopenia (HIT). The 4T score, which is based on degree and timing of thrombocytopenia, and whether there are other explanations for thrombocytopenia or the presence of thrombosis, is a commonly used tool to assess the clinical probability of HIT prior to performing laboratory testing. Published guidelines recommend further testing with an anti-PF4/heparin enzyme immunoassay (EIA) and confirmation with the serotonin-release assay (SRA) when the pretest probability of HIT is intermediate or high. The diagnosis of HIT confers high morbidity and mortality; therefore it is crucial to establish a definitive diagnosis in patients with suspected HIT. However, empiric treatment with alternative non-heparin anticoagulants increases the cost of hospitalization and may cause unnecessary risks in patients with a false positive EIA. The purpose of our study was to evaluate the utilization of EIA and SRA at a large tertiary care center and to assess the agreement between the 4T score, the EIA, and the SRA.