In this episode, I’ll discuss whether a urine dipstick test can identify patients with clinically significant amounts of plasma DOAC levels.
Direct Acting Oral Anticoagulants such as apixaban, rivaroxaban, edoxaban, and dabigatran do not have readily available assays, yet there is often a clinical need to determine the presence or absence of clinically relevant concentrations of these medications, particularly in patients who present to the ED with severe bleeding or clotting problems.
In episodes 536 and 637 I discussed how the oral anti-Xa inhibitors can be detected using non-calibrated and calibrated heparin Xa plasma assays.
However, a recent correspondence in the journal Academic Emergency Medicine pointed out that there is another possible way to make this determination – one that would also pick up on dabigatran concentrations as well.
In a prospective single-center cohort study that included more than 100 consecutive patients treated with apixaban, rivaroxaban, or dabigatran, the urine test strips had a 100% sensitivity and negative predictive value to exclude patients with clinically relevant DOAC plasma levels. The specificity and positive predictive values were much lower however, making this test more valuable for excluding the possibility of a significant level of DOAC being in a patient’s system.
This is an interesting alternative to using plasma anti-Xa levels to detect significant amounts of anticoagulation, and it has the advantage of including the detection of dabigatran. Like plasma anti-Xa levels, the clinical utility is to rule out the presence of significant levels of anticoagulation from a DOAC in order to inform decisions surrounding invasive procedures or thrombolytic therapy.
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