Appropriateness of Thrombophilia Testing in Tertiary Care Centers in Edmonton

INTRODUCTION

Thrombophilia is associated with an increased risk of venous thromboembolism (VTE). Despite this link, determining the presence or absence of such conditions has no role in VTE management including determining the choice or duration of anticoagulant therapy. Testing can be potentially harmful when results are misinterpreted or impact patient anxiety and insurance eligibility.

METHODS

We performed a retrospective chart review of adult patients presenting to the emergency department (ED) or were admitted to the University of Alberta Hospital (UAH), Royal Alexandra Hospital (RAH) and Grey Nuns Hospital (GNH) and underwent any number of thrombophilia tests (including factor V Leiden [FVL], prothrombin gene mutation [PT20210], protein C [PC], protein S [PS], antithrombin [AT] and antiphospholipid antibody testing). To assess for appropriateness of testing, categories of data were collected including presence of other strong risk factors obviating the need to look for other causes, indicators for higher yield (age of patient, presence of family history of VTE, idiopathic nature of VTE), presence of factors that confound testing (such as therapeutic anticoagulation) and relevant follow up (appropriate repeat testing when necessary). We also collected basic patient demographics, VTE details and ordering physician/service details to evaluate under what circumstances testing may be ordered more frequently.

RESULTS

134 charts of patients tested for thrombophilia were reviewed between 2007-2013 at UAH and RAH Hospitals. A total of 965 thrombophilia tests were done (see analysis table). 13.4% of the testing was ordered by hematologists, 23.1% by neurologists, 52.2% by other internists. Overall, all patients had tests performed inappropriately, lacked appropriate follow up or had uninterpretable results and none had documented counseling prior to thrombophilia testing.

CONCLUSIONS

Thrombophilia testing is frequently ordered inappropriately and not adequately followed up. Strategies to educate physicians on indications and limitations of testing are warranted.  These strategies can help decrease over/under/misinterpretation of thrombophilia testing as well as result in significant savings to the health care system if testing can be reduced.

Demographics
Sample Size	Males	Females	Total
	74 (55.22%)	60 (44.78%)	134 (100%)
Age at time of testing (Yrs)	Range		19-88
	Average		48.7
Patients’ Test Results
Test		Times Performed	Abnormal Results
APCR		134 (100%)	32 (23.8%)
FVL genetic test		58 (43%)	21 (39%)
PT20210		105 (77%)	4 (3.8%)
Protein C		100 (74.1%)	8 (8%)
Protein S		99 (73.3%)	16 (16.2%)
AT levels		99 (73.3%)	19 (19.2%)
Anticardiolipin Ab		117 (86.7%)	4 (3.4%)
Lupus Anticoagulant		109 (81.3%)	10 (10.2%)
Provoking Factors
Patients with One or More Provoking Factors	Major	10	7.4%
	Moderate	74	56%
	Minor	29	21.8%
No Provoking Factors		49	36.8%
Family History of VTE		12	8.9%
Protein C and Protein S Testing
Done During Acute VTE		64	64%
Patient was on Warfarin		25	25%
Number of Abnormal Test Results		24	16%
Number of Repeated Abnormal Tests		0	0%
AT Testing
Total Tests Performed		99	73.3%
Done During Acute VTE		62	63%
Patient was on Therap. Heparin or LMWH		62	62.6%
Number of Abnormal Test Results		19	19.2%
Abnormal Tests Repeated?		7	37%
Repeat Tests Showing Normal Results		3	57%
APA Testing
Tests were Repeated After 12 Weeks for Confirmation			11%

Disclosures: Wu: Leo Pharma: Consultancy , Honoraria , Membership on an entity’s Board of Directors or advisory committees ; Pfizer: Consultancy , Honoraria , Membership on an entity’s Board of Directors or advisory committees .

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