Direct oral anticoagulants (DOACs) such as dabigatran etexilate, rivaroxaban, apixaban, edoxaban, and betrixaban often interfere with clot-based
or chromogenic coagulation assays and may lead to inaccurate results or render the test uninterpretable. Affected tests include many commonly
ordered tests on hypercoagulable workup panels: Lupus anticoagulant (LA) panels, activated protein C resistance, protein C and protein S activity,
antithrombin activity, and specific factor activity levels. These tests should not be done in patients taking DOACS. If there is a compelling reason
to perform these tests, great caution must be taken to avoid acting on a false result. For instance, specimens should be collected at the medication
trough, and potential test interference should be considered prior to ordering. The potential for interference is dependent on test methodology,
drug mechanism of action, and drug concentration. For patients suspected clinically to have antiphospholipid antibody syndrome, the lupus
anticoagulant panel may be uninterpretable, but ELISA-based anticardiolipin and anti-beta2 GP1 antibody testing is unaffected. Genetic testing,
such as PCR for factor V Leiden, is also unaffected.
