In vitro tests for assessing heparin-induced thrombocytopenia in patients after elective hip replacement. A medico-economical evaluation.

OBJECTIVES

Considering the previously published incidences of heparin-induced thrombocytopenia (HIT) in patients receiving a thromboprophylactic therapy, the role of the hemostasis laboratory is essential in making a clinical decision. The purpose of this project was to compare the strategies of diagnosis and associated care of patients with suspected HIT after elective hip replacement using platelet aggregation assay, carbon 14-serotonin release, and "doing nothing."

METHODS

The authors used an incremental cost-effectiveness analysis based on data extracted from the literature. The effectiveness of the strategies was represented by the number of deep venous thromboses prevented. Cost data were collected from the observation of biological and medical practice at Edouard Herriot University Hospital, Lyon, France, in 1999.

RESULTS

In comparison with the strategies of doing nothing using no biological test for diagnosis, and clinical care of HIT-suspected patients, the strategy using platelet aggregation test was more expensive and less effective. With respect to the strategy using carbon 14-serotonin release assay, the incremental cost-effectiveness ratio, expressed as U.S. dollars per deep venous thrombosis prevented, reached $200,000, with a marginal effectiveness of eight deep venous thromboses prevented for 10,000 HIT-suspected patients.

CONCLUSION

This study suggests that clinical hemostasis laboratories might consider replacing the platelet aggregation test with the carbon 14-serotonin release assay or should use another functional assay such as the flow cytometric assay for the diagnosis and care of patients with suspected HIT.