The Effect of Polybrene on an aPTT-based Lupus Anticoagulant Test in the Plasma of Patients Receiving Unfractionated Heparin

Objective: Heparins can interfere with lupus anticoagulant (LA) testing, especially when the detection assays do not contain a heparin neutralizer. In this study we evaluated whether hexadimethrine bromide commonly known as polybrene was able to neutralize the effects of unfractionated heparin (UFH) on activated partial thromboplastin time (aPTT)-based LA determination. Material and Methods: The influence of polybrene on the aPTT-based LA testing results of 14 patients receiving UFH therapy was studied. Measurements were performed using Dade Actin FSL (aPTT-LA screen) and Dade Actin FS (aPTT-LA confirm) reagents on a Sysmex CS-1600 analyzer. The aPTT-LA screen/confirm ratios before and after the polybrene treatments were compared. Results: The UFH treatment affected the aPTT-LA screen/confirm ratio in four patterns, 1) no coagulation (NC code), 2) false positive, 3) false low, and 4) unchanged interpretation. After adding polybrene in the patient plasmas, the aPTT-LA screen/confirm ratios returned nearly to baseline without false positive or negative results. Conclusion: The best practice for LA testing should be done outside anticoagulant therapies, but if necessary, the tests can be performed by adding the proper concentration of polybrene.