Background and Purpose: Thrombophilic states are an uncommon primary mechanism of ischemic stroke in adults. The role of screening for inherited thrombophilia is unclear, but may be considered in cryptogenic stroke. The aim of this study was to assess the clinical utility and costs of thrombophilia testing. A secondary aim was to characterize the demographics and risk factors of tested individuals.
Methods: Two year, two center, retrospective, observational study of ischemic stroke patients with thrombophilia testing obtained during inpatient admission. Economic burden was calculated as the product of current laboratory costs and test incidence. Effect of panel outcome on treatment was recorded.
Results: Thrombophilia testing was conducted in 7.8% (226/2900) of all ischemic stroke patients during the study period. 2,808 thrombophilia tests were conducted on 226 patients in a two year period with total cost of $454,138. Clinical management was changed solely based on panel results in four cases (1.8%) and hematology was consulted in 19 cases (8.4%). Most panels (71.2%) were ordered within the first 48 hours of admission while diagnostic testing was ongoing. There was a high prevalence of stroke risk factors in the tested population (Table). 30% of testing was deemed unnecessary due to determination of a non-thrombophilic mechanism for stroke. There was a trend towards venous thrombophilia tests ordered more frequently in subjects with a patent foramen ovale (PFO), but overall venous thrombophilic testing was ordered at a high frequency (87.5% venous panel/ +PFO vs 75.3% venous panel/- PFO, p 0.07).
Conclusions: Thrombophilia testing yielded low clinical impact while incurring high economic burden in an adult ischemic stroke population. Institutional optimization, particularly with timing of lab ordering, breadth of diagnostic panel, and testing indicators, may enhance use of these tests for clinical decision making while limiting unnecessary health care costs.