Accurate Laboratory Detection of Lupus Anticoagulant in Anticoagulated Patients: An Area for Adopting System based Collaboration in Thrombosis
Year: 2025
Type: article
Abstract: Sir, Lupus anticoagulant (LA) antibody is a known cause of thrombosis in patients with antiphospholipid syndrome. Identification of LA plays an important role in the diagnosis of antiphospholipid syndrome. Currently, using at least two tests with different principles to detect (LA), namely the Dilute Russell’s Viper Venom Time test and the activated partial thromboplastin time is recommended before excluding its presence.[1,2] The LA testing is a multistep procedure that includes a screening step, a mixing study, and a confirmatory step.[2,3] However, using anticoagulant medication presents challenges for accurate identification of LA.[2] Anticoagulant therapies such as direct oral anticoagulant (DOAC), Vitamin K antagonist (VKA), and heparin interfere with LA detection, giving false-positive or false-negative results.[3] The DOAC-stop commercial test was proposed a few years ago to encounter interference of DOAC (such as apixaban, dabigatran, and rivaroxaban) with LA detection, but this commercial reagent may contribute to factor deficiency with a slight effect on the screening step which will result in increased normalization ratio, effecting the interpretation of the test results.[4] In addition, it may contribute to erroneous results in non-DOAC-treated patients.[4] Hence, this remains an area that needs further investigations and improvement.[4] Although dilution of the test plasma into pooled normal plasma is suggested, it is not a reliable procedure to eliminate the effect of anticoagulant for patients on VKA or warfarin as it can give false-negative results due to negativity of the mixing step or false-positive results because of high anticoagulation intensity that gives positive mixing step.[3,5] Among the used anticoagulants, low molecular weight heparin (LMWH) has the least effect on the interference with LA detection.[3] The use of heparin neutralizer in some commercial tests may eliminate the effect of unfractionated heparin or LMWH up to 1.0 U/mL.[3] Although, the interpretation of the LA test should be with caution for those patients on LMWH using heparin neutralizer and with measurement of anti-Xa activity to ensure that LMWH within the therapeutic range.[3] The last updated guidelines for the identification of LA recommended that final reporting of the positive or negative result of LA has to be aligned with possible interference by anticoagulant with a need of harmonized clinician-laboratory professionals’ collaboration to incorporate patients’ anticoagulant information at testing time.[5] Tripodi et al. suggested not to attempt for LA detection during DOAC.[3] We do believe that the education of the clinicians, implementation, and adoption of system-based collaboration for appropriate LA testing in anticoagulated patients is very important to optimize the accuracy of the test and patients’ outcomes. Hematologists and coagulation specialists can guide on the proper timing of testing to help the laboratory professionals in results’ interpretation in the context of anticoagulant therapy with support from clinical pharmacists by identifying the optimal sampling time through considering the pharmacokinetics of the anticoagulant therapy. Hematologists can also offer guidance if the patient is a suitable candidate for temporary withholding of VKA or DOAC and using bridging therapy with the anticoagulant with the least effect on LA which is LMWH. For sure, this requires close collaboration between all teams to balance the risk of thrombosis with the need for accurate testing. The hematopathologists and laboratory professionals will engage in selecting the appropriate test & reagents, educating the clinicians about the effect of anticoagulant therapy, and better to advise avoiding such testing while the patients in the early phase of anticoagulant therapy to interpret the test with a high accuracy. Utilization of the electronic-based system by implementation of pretest requirements that entered during patient’s sampling to determine while the patient is in anticoagulant, type of anticoagulant, and timing of the last dose of anticoagulant will facilitate such collaboration and will ease the laboratory diagnostic workup. By engaging multiple healthcare disciplines with adopting system-based collaboration, considering the complexity of LA test interpretation on anticoagulated patients, we will not only improve the diagnostic process but also foster better utilization of resources, better healthcare services, and more informed clinical decision-making. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Source: Journal of Applied Hematology
Institution: Qatif Central Hospital
Language: English
Subfield: Rheumatology
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W4411386743