Rising rates of DOACs use are increasing the risk of misinterpretation of abnormal pathology test results
Dramatically rising rates of direct oral anticoagulant (DOAC) use are increasing the risk of misinterpretation of abnormal pathology test results, according to a leading Australian clinician.
Speaking at the annual conference of the College of Pathologists of Australasia in Sydney last month, Dr Emmanuel Favaloro told the audience that an under-recognised problem with DOACs was that they affected routine coagulation tests.
In addition to the effect of these drugs on haemostasis, which resulted in changes to routine coagulation tests such as prothrombin time (PT) and/or activated partial thromboplastin time (APTT), DOACs could also affect more complex assays such as factor assays.
It is possible for pathology test results related to clotting disorders to be misinterpreted.
This includes those used to diagnose lupus anticoagulant, a risk factor for thrombosis.
“It is possible for pathology test results related to clotting disorders to be misinterpreted,” he said, adding that this could sometimes lead to the wrong diagnosis being made.
“Anti-coagulation therapy is generally commenced in patients who have had a thrombotic event […] or patients who are at risk of having a thrombotic event,” Dr Favaloro said.
And while DOACs did not need their effect monitored with regular blood tests, making them less intrusive and more convenient, there were a range of complexities around their use, he added.
“Due to the potential for less interaction with the patient, compared to patients on warfarin, it can become a complex situation for general clinicians to navigate, as they may be trying to interpret results of a test, or to make a diagnosis related to a thrombotic or bleeding event.”
Different clinicians might not be aware that a patient was on a DOAC, which could complicate the situation further, Dr Favaloro said.
Dabigatran affected APTT more than PT, whereas rivaroxaban affected PT more than APTT, he said.
DOACs also interfered with clot-based assays for protein C and protein S.
