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The effect of direct oral anticoagulants (DOACs) on laboratory tests dependent on the production of their targets, factor IIa and factor Xa (FXa), is a well-known problem and can cause both false positive and negative results. Therefore, the correct interpretation of tests performed in patients receiving DOACs is necessary to avoid misclassification and subsequent clinical consequences. However, even with significant experience, there are situations where it is not possible to assess the influence of some methods. Particularly important is the situation in the diagnosis of lupus anticoagulants using the dilute Russell viper venom timetest, which is based on direct FXa activation. A very promising solution to this situation is offered by the DOAC laboratory balancing procedure DOAC-Stop. For evaluating the effectiveness of this procedure, 60 (20 apixaban, 20 dabigatran, and 20 rivaroxaban) patients treated with DOACs were enrolled. All patient samples were analyzed for the presence of individual DOAC types and subsequently subjected to the DOAC-Stop procedure.We evaluated its effectiveness by our own high-performance liquid chromatography-coupled tandem mass spectrometrymethod, which simultaneously sets all high-sensitivity DOACs. Unlike coagulation tests based on the determination of the residual effects of DOACs on target enzymes, which is complicated by extensive interindividual variation, this methodology is highly specific and sensitive.The DOAC-Stop procedure eliminated dabigatran from 99.5%, rivaroxaban from 97.9%, and apixaban from 97.1% of participants in our group. Residual amounts did not exceed 2.7 ng/mL for dabigatran, 10.9 ng/mL for rivaroxaban, or 13.03 ng/mL for apixaban, which are safe values that do not affect either screening or special coagulation tests.

Antiphospholipid syndrome (APS) is a hypercoagulation condition associated with the incidence of heterogenic antiphospholipid antibodies (aPLs), which non-specifically affect hemostasis processes. APS is clinically manifested by recurrent arterial and venous thromboses and reproduction losses. The aPL antibodies, which may induce clinical manifestations of APS, include criteria antibodies anti-cardiolipin, anti-β2-glycoprotein-I, and lupus anticoagulant, but also non-criteria antibodies, for example anti-β2-glycoprotein-I domain I, anti-phosphatidylserine/prothrombin, anti-annexin V, and many others. APS occurs mostly in patients of younger and middle age, most frequently in females. Laboratory diagnostics of APS are quite difficult, as they include a wide spectrum of examining methods, which are based on various principles of detection and are performed using various laboratory techniques. The objective of the review is to describe the current state of potentially examined biomarkers and methods in APS diagnostics. The aforementioned biomarkers are lupus anticoagulant, anti-β2-glycoprotein-I, anti-cardiolipin, anti-β2-glycoprotein-I domain I, anti-phosphatidylserine/prothrombin, anti-β2-glycoprotein-I IgA, anti-cardiolipin IgA, anti-annexin V and II, anti-prothrombin, anti-cardiolipin/vimentin, anti-protein S/protein C, and antibodies against phospholipid antigens for whose diagnostics we may use some of the methods established for a long time and some of the modern methods—the coagulation method for the determination of lupus anticoagulant (LA), enzyme-linked imunosorbent assay (ELISA), chemiluminescence analysis (CLIA), multiplex fluorescence flow immunoassay (MFFIA), fluorescence enzyme immunoassay (EliA), line immunoassay (LIA), multiline dot assay (MLDA), and thin-layer chromatography (TLC). Conclusion: Antibodies against phosphatidylethanolamine, phosphatidic acid, phosphatidylserine, phosphatidylinositol, cardiolipin/vimentin complex, and annexin V are currently the most studied new markers. However, these assays have not been standardized until now, both from the laboratory and clinical point of view. In this review we summarize the evidence of the most studied aPL markers and their potential clinical significance in seronegative APS (SN-APS).

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