Assessing The Clinical And Economic Impact Of An Automated, On-Demand Immunoassay For The Diagnosis Of Heparin Induced Thrombocytopenia

Abstract

To understand and quantify the clinical and economic impact of an automated, on-demand diagnostic test versus current diagnostic tests, for heparin-induced thrombocytopenia (HIT). A mixed methods study combining a literature review with primary research. The literature review searched multiple databases to identify data on test performance, clinical and economic data. Semi-structured interviews (n=4) provided insight into current practice and challenges faced, validated by a larger survey (n=90). Two flow diagrams modelling a hypothetical cohort of 1000 patients were used to calculate the clinical and cost impact of automated, on-demand testing. The automated, on-demand test had comparable or lower sensitivity, and a higher specificity than other available tests. Clinical data and survey findings indicate that the specificity of the most widely used antibody tests (ELISA) is suboptimal. The survey revealed that half of patients are speculatively switched off of heparin and onto replacement therapy based on clinical assessment alone, rather than based on clinical assessment and diagnostic test results as per guideline recommendations. Speculative treatment is driven by test turnaround time of >24 hours for >50% of respondents. The cost model indicated that the cost of replacement therapy whilst awaiting tests results of >24 hours’ turnaround time was between $7215 and $31268. Automated, on-demand antibody testing and switching patients off heparin based on test results reduced this cost to between $2737 and $13092. Automated, on-demand HIT antibody testing could enable physicians to use timely diagnostic test results with better specificity than current tests to make treatment decisions. This could potentially enable earlier treatment of HIT to reduce complications such as extended hospitalisation and death, thus improving clinical outcomes and reducing costs. Also, earlier informed treatment decisions could yield pathway cost reductions through reducing the use of replacement therapies in non-confirmed and false positive cases.