Direct oral anticoagulant (DOAC) use is increasing but, although DOAC plasma level assays are available, information on DOAC measurements in clinical practice is scarce. To describe patient characteristics and clinical situations where DOAC assays were ordered and determine whether the assays indications and subsequent patient management were consistent with current guidelines.

Retrospective study of data for patients with prescriptions for three DOACs: dabigatran, rivaroxaban and apixaban treated at Percy Military Hospital between 2016 and 2019.

During the study period, 196 DOAC measurements were performed on 148 patients (median age: 82.5 years). The most frequently prescribed DOAC was rivaroxaban (57.5%) and the commonest indication was nonvalvular atrial fibrillation (77%). Measurements were performed on 3.5% of patients with an active prescription for DOAC, and DOAC prescriptions complied with the product's characteristic summary in 62.8%. The number of assays performed increased 2.5-fold between 2017 and 2019. Most DOAC assays were ordered due to emergency surgery or procedures (46.9%), bleeding (19.9%) or a risk of drug accumulation (13.8%). Reasons for ordering DOAC measurements were consistent with the guidelines in 87.2% of the cases. Subsequent clinical decisions were consistent with the guidelines in 86.2% of the cases.

DOAC assays orders were rare but are increasing. Acute clinical situations were the most common source of test orders. Management followed correct interpretation of the results in most, but not all, cases, indicating a need for additional education to raise awareness of test indications and result interpretation for clinicians.