Assessing the Clinical and Cost Impact of On-demand Immunoassay Testing for the Diagnosis of Heparin Induced Thrombocytopenia

Background: The diagnostic work-up for heparin induced thrombocytopenia (HIT) can take several days. Consequently patients may be speculatively switched onto replacement anticoagulant therapy before a diagnosis is confirmed. On-demand immunoassay diagnostic testing enables timely treatment decisions, based on test results.

Objective: To estimate the clinical and cost impact of the use of on-demand versus batched diagnostic tests for HIT.

Methods: Literature was reviewed to identify test performance, clinical and cost data. Semi-structured interviews (n=4) and a survey (n=90) provided insights into current practice and challenges. Flow diagram models were developed to estimate the potential impact of on-demand testing.

Results: Modelling estimated more HIT-related outcomes for patients maintained on heparin whilst awaiting test results and patients switched onto replacement anticoagulant therapy awaiting test results, compared with on-demand testing and treatment based on the results. The budget impact model estimated that on-demand testing reduced replacement anticoagulant therapy costs from $39,616 to $12,799 per patient. There are limitations to the data available to inform modelling and the estimates should be treated with caution.

Conclusions: Using on-demand testing may drive positive effects on clinical and cost outcomes.