PB1147 - Effect of high-dose direct anticoagulant drugs and DOAC-Remove on lupus anticoagulant detection by a hexagonal phase phospholipid assay

Background: Argatroban and DOACs are known to interfere with LA testing. cryocheck Hex LA™ is a hexagonal phase phospholipid neutralization test (HPNT) with a heparin neutralizer which detects LA in citrated plasma samples by a Delta Correction (ΔCT) of a prolonged APTT using hexagonal phase phospholipid. Previously, we reported that Fondaparinux (1.25mg/mL), Dabigatran (200ng/mL) and Rivaroxaban (400ng/mL) did not diagnostically impact Hex LA, although DOACs could prolong clotting times (CTs) and ΔCT of LA-positive samples. The capacity and diagnostic compatibility of DOAC-Remove™ treatment of samples prior to the Hex LA assay are unknown.

Aims: To evaluate the effect of high doses of direct anticoagulant drugs on the detection of LA by cryocheck Hex LA, with and without treatment by DOAC-Remove.

Methods: LA-negative and LA-positive pooled plasma samples were spiked at two final concentrations of 500ng/mL and 1000ng/mL for each of Apixaban, Argatroban, Dabigatran, Edoxaban or Rivaroxaban. Each sample was tested (N=7) by Hex LA on a Stago STA-R Evolution analyzer, with and without DOAC-Remove treatment per manufacturers’ instructions.

Results: The effect of DOAC-Remove treatment vs. non-treatment on ΔCT was not statistically significant (p < 0.05) for either neat LA-negative or LA-positive samples, (2.0 vs 2.9 seconds and 31.5 vs 29.9 seconds, respectively), indicating that DOAC-Remove does not adversely impact LA analytical sensitivity of Hex LA. Argatroban and DOACs increased ΔCT results in a dose-dependent manner, especially in LA-positive samples. DOAC-Remove effectively prevented CT and ΔCT prolongation of Hex LA, provoked by Argatroban and DOAC, in both LA-negative and LA-positive samples.

Conclusion(s): Hex LA accurately detected LA in the presence of high-dose DOACs and Argatroban (500-1000ng/mL). However, the increased ΔCT with high-dose DOACs could present a risk of false positive results. DOAC-Remove mitigated this risk by returning Hex LA results to those observed in the absence of DOACs/Argatroban.