Researchers say they have developed an algorithm to support use of a simple dipstick test for DOAC levels, that can return a clinically-useful reading in 10 minutes.
The Australian and international team has presented early data showing promising sensitivity and specificity from the test, which uses a disposable strip to identify factor Xa or thrombin inhibitors in a urine sample.
Already approved for use in Australia, the test has a 10-minute reaction time at room temperature after urine immersion, at which point there is a specific colour change on the respective test pad if a DOAC is present. Other pads indicate urine colour and creatinine, each of each of which can impact testing accuracy.
If the test is negative (with normal creatinine pad results), then clinically significant DOAC levels (≥30 ng/mL) have been excluded, according to the team.
“This test excludes clinically relevant blood concentrations of DOACs, which can speed up clinical decision-making in critical medical situations such as major bleeding, acute ischaemic stroke with consideration for intravenous thrombolysis, or urgent surgical procedures,” they wrote in Thrombosis and Haemostasis (link here).
“Advantages of the method are that it does not require knowledge of the specific DOAC taken by the patient, is a point-of-care format, and has a rapid turnaround time, thereby enabling its use even in small facilities such as community hospitals.”
The authors performed a pooled analysis on five studies published in 2022 and 2023, comparing DOAC Dipstick with LC-MS/MS or DOAC-calibrated chromogenic assays.
Together, these indicated an acceptably high negative predictive value for exclusion of DOACs requiring verification of a match with the patient’s clinical picture (see table below).