Background: Thrombophilia testing in hospitalized patients is often inaccurate and rarely clinically useful especially in acute settings. Testing for inherited thrombophilia is often done in the setting of recurrent unprovoked venous thromboembolism (VTE). Several prospective studies have shown that heritable thrombophilia status is not statistically associated with recurrent VTE. Additionally, such testing may be confounded by ongoing disease or treatment. The cost per thrombophilia panel testing range anywhere between $1100 to$2400 based on estimation of charges billed by a large commercial laboratory. We aim to identify patterns and costs involved in inpatient thrombophilia testing in a community teaching hospital.

Methods: The study was conducted as a part of our quality improvement initiative in a community teaching hospital. We performed a retrospective chart review of patients above the age of 18 years who had a clinically and radiologically confirmed diagnosis of venous thromboembolism during the year of 2016 and performed descriptive analysis. Institutional IRB was obtained and data was collected by reviewing the electronic medical records .

Results: A total of 395 patients with the diagnosis of VTE were included (mean age 68.5, 54.2% female). At least one thrombophilia test was ordered in 66 of the 395 patients (16.7%). Around 38 (9.6%) patients were already on anticoagulation for atrial fibrillation/flutter, deep venous thrombosis (DVT) and pulmonary embolism (PE) among whom 5/38 (13.2%) patients underwent thrombophilia testing. Number of patients with a prior history of DVT or PE or both were 67/395(20%). Out of these, 26/67 (38.8%) patients were on anticoagulation and 14/67 (20.9%)patients underwent thrombophilia testing during their hospital stay. Only 11/395 (2.8%) patients had a family history of DVT/PE among whom 4 were tested. The approximate cost of the testing was $132,000 considering roughly$2000 per test on an average for a total of 66 tests.

Discussion: Thrombophilia testing in hospitalized patients adds little if at all any value to their acute management. However, it does add a significant unnecessary avoidable cost to the hospital. Although inpatient thrombophilia testing is not supported by current guidelines for inherited thrombophilia evaluation, the testing is often done in hospitalized patients with recurrent thromboembolism. Learning the pattern of thrombophilia testing in hospitalized patients will help us implement measures to prevent unnecessary testing and the significant costs associated with it.

Conclusion: With the increasing emphasis on value-based health care, thrombophilia testing should be considered only if it affects overall patient management and preferably in an outpatient setting with appropriate indications.

Disclosures

No relevant conflicts of interest to declare.

## Author notes

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Asterisk with author names denotes non-ASH members.