Hit or Miss: Evaluation of Testing and Management of Heparin-Induced Thrombocytopenia in Hospitalized Patients

Document Type

Conference Proceeding

Publication Date

3-6-2026

Publication Title

Am J Health Syst Pharm

Keywords

anticoagulant agent, heparin, heparin platelet factor 4 antibody, adult, adverse drug reaction, anticoagulation, bleeding, complication, conference abstract, diagnosis, female, heparin induced thrombocytopenia, heparinization, hospitalization, human, immunoassay, intensive care unit, observational study, optical density, overdiagnosis, prematurity, prevention, probability, release assay, retrospective study, serotonin release, therapy

Abstract

Purpose: Heparin-induced thrombocytopenia (HIT) is a potentially life-threatening complication associated with heparin therapy. The low specificity of the HIT antibody assay often contributes to overdiagnosis, as clinicians may interpret a positive result as a definitive diagnosis of HIT without considering the pre-test probability or optical density of the result. This can lead to premature discontinuation of heparin, inappropriate use of alternative anticoagulants, and prolonged hospitalization. The purpose of this study is to assess the appropriateness of HIT testing and determine if subsequent clinical decisions align with guideline recommendations. Methods: This multi-site retrospective observational study will include 100 hospitalized adult patients admitted between January 1, 2020 and July 31, 2025 with a positive HIT antibody result (defined as optical density greater than or equal to 0.4). Data collection will include baseline demographics, anticoagulation prior to admission, indication and duration of heparin exposure, laboratory values, provider service type, and durations of ICU admission and hospitalization. The 4T score will be calculated to assess pre-test probability of HIT. Serotonin release assay results will be collected, if available. Safety will be assessed based on frequency of bleeding and new thrombotic events. For patients transitioned to a non-heparin anticoagulant, the agent, timing of transition (relative to HIT antibody test), and duration of use will be recorded. Patients who are appropriate candidates for oral anticoagulation will be identified based on prespecified criteria. All data will be summarized with descriptive statistical methods.

Volume

83

Issue

Supplement_2

First Page

S810

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