Direct oral anticoagulant drug level testing in clinical practice: A single institution experience

Abstract

We performed a review of all direct oral anticoagulant (DOAC) levels – ecarin times for dabigatran and anti-Xa levels for rivaroxaban and apixaban – ordered at our institution with the purpose of evaluating DOAC levels from “real-world” (non-clinical trial) patients taking DOACs long-term, in order to assess levels obtained, reasons for checking levels, and actions taken based on the testing result. A total of 28 patients had 48 levels sent over a 36-month period. The majority of outpatient levels were within or close to the range of published values. The setting in which levels were sent influenced how results affected management decisions: in the outpatient setting, the majority of levels served to reassure clinicians that DOAC levels were within expected ranges resulting in continuation of chosen management, whereas in the inpatient setting, DOAC levels were used most frequently to detect DOAC presence in urgent clinical situations and influenced clinical decision-making in the peri-procedural and pre-operative periods. Our results demonstrate that while testing may be useful if immediately available in urgent clinical situations where assessment of drug presence is needed, DOAC level monitoring is infrequently used overall, and the lack of use combined with the paucity of available evidence to guide clinical decision-making based on the results suggests there is little urgency to make the tests widely available for routine use outside of acute settings in the emergency department and urgent surgical setting.

Laboratory measurement of the direct oral anticoagulants: Indications and impact on management in clinical practice

“…In spite of these limitations, our study, together with the report of Martin and Moll, casts light on the use of DOAC measurement in real‐world clinical practice. Key observations include the relative infrequency with which measurement is requested, common indications for testing in the inpatient (surgery, breakthrough thrombosis, bleeding) and ambulatory settings (extremes of bodyweight, suspected malabsorption), and the role drug levels may play in patient management.…”

“…To our knowledge, real‐world clinical experience with laboratory measurement of DOACs at only one other institution has been published. Martin and Moll reported on 48 DOAC levels in 28 patients at the University of North Carolina (UNC) Chapel Hill . They too found that DOAC measurement was uncommon and was reserved for special circumstances.…”

Evaluation of global laboratory methods and establishing on‐therapy ranges for monitoring apixaban and rivaroxaban: Experience at a single institution

“…9 No therapeutic ranges for DOACs have been published based on the results of clinical trials and potential interferences by clinical and laboratory parameters have not been well characterized. 10,11 Manufacturers and previous reports provide only peak and/or trough plasma concentrations as determined by liquid chromatography/tandem mass spectrometry (LC-MS/MS), and thus, term of ontherapy range was used in the current study, as has been previously described. 10,12 Liquid chromatography/tandem mass spectrometry is the gold standard method for measuring plasma DOAC levels, but DOAC levels vary widely from trough to peak among individualpatients.…”

A level‐headed approach to measuring direct oral anticoagulants: A 2‐year retrospective analysis of DOAC levels from a tertiary UK centre

“…Previous retrospective real-world studies of the utility of DOAC levels have found that levels are infrequently requested and are of limited utility. 36,37 However, this may reflect a lack of clinician awareness of the availability of these tests, the long TAT and an unfamiliarity with result interpretation. 36 In contrast, in our study, DOAC levels were widely used and influenced clinical decision making.…”

“…36,37 However, this may reflect a lack of clinician awareness of the availability of these tests, the long TAT and an unfamiliarity with result interpretation. 36 In contrast, in our study, DOAC levels were widely used and influenced clinical decision making. This may be because of our relatively quick TAT, clinician awareness and Our study has a number of limitations.…”