Practical Considerations and Testing Nuances for the Detection of Lupus Anticoagulant: Do Low Phospholipid Screen Results, Assay Type, and Test Ratio Matter?

OBJECTIVES: Lupus anticoagulant (LA) detection requires (1) prolongation of a phospholipid (PL)-dependent clot-based screening assay, (2) noncorrection upon adding normal pooled plasma, and (3) a confirmatory PL dependency test. Paired LA assays run screening and confirmatory tests simultaneously, with their test ratio (TR) or differences used to evaluate test results. We evaluated patients whose paired testing demonstrated PL dependence suggestive of LA, yet the low PL screen was not prolonged. METHODS: Clinical and laboratory parameters are compared across (1) true positive (screen prolonged, TR positive) vs borderline (screen not prolonged, TR positive); (2) low-, moderate-, and high-TR subgroups; and (3) dilute Russell viper venom time (dRVVT) vs silica clotting time (SCT). RESULTS: Borderline samples are not statistically different from true positives in their rate of repeat LA positivity or association with other anti-PL antibodies. Compared with true positives, borderline dRVVT is more frequent in pregnancy, women, and younger age. Elevated activated partial thromboplastin time is more frequent in true-positive dRVVT and SCT vs borderline and with an increasing dRVVT TR. LA persistence is more frequent with an increasing SCT TR. In addition, dRVVT true positivity is more frequent with thromboembolic events, while SCT is more frequent with autoimmunity and pregnancy complications. CONCLUSIONS: Negative low-PL screens may not necessarily lack LA. A reevaluation of the laboratory criteria for LA detection may be needed.

Antiphospholipid Syndrome Committee of the Brazilian Society of Rheumatology position statement on the use of direct oral anticoagulants (DOACs) in antiphospholipid syndrome (APS).

BACKGROUND: The term Direct Oral Anticoagulants (DOACs) refers to a group of drugs that inhibit factor Xa or thrombin. Even though their use for treating different thrombotic or prothrombotic conditions is increasing recently, there is no compelling evidence indicating that those medications are safe in all antiphospholipid syndrome (APS) patients. METHODOLOGY: To address this issue, specialists from the Antiphospholipid Syndrome Committee of the Brazilian Society of Rheumatology performed a comprehensive review of the literature regarding DOACs use in APS to answer the three following questions: (1) potential mechanisms of action of these drugs that could be relevant to APS pathogenesis, (2) DOACs interference on lupus anticoagulant testing, and (3) the efficacy of DOACs in APS. POSITION STATEMENT: After critically reviewing the relevant evidence, the authors formulated 8 Position Statements about DOACs use in APS. CONCLUSION: DOACs should not be routinely used in APS patients, especially in those with a high-risk profile (triple positivity to aPL, arterial thrombosis, and recurrent thrombotic events). In addition, DOACs interferes with LA testing, leading to false-positive results in patients investigating APS.

[Seronegative antiphospholipid syndrome: Myth or reality?] / Syndrome des antiphospholipides « séronégatif ¼ : mythe ou réalité ?

The antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by thrombosis and/or obstetrical manifestations and the persistent presence, at least 12 weeks apart, of antiphospholipid antibodies (aPL) such as lupus anticoagulant (LA) and/or anticardiolipin antibodies (ACL) and/or anti-ß2 glycoprotein I antibodies (aß2GPI). The finding of patients with clinical profile highly suggestive of APS but who are negative for conventional biological criteria has led to the concept of seronegative APS. In the last few years, new antigen targets and methodological approaches have been employed to more clearly identify this syndrome in patients with thrombosis or obstetrical complications without conventional aPL. Although seronegative APS is still controversial, there is increasing recognition of the existence of this subgroup. However, clinical relevance of non conventional aPL need to be confirmed by efforts toward standardizing new biological tools and longitudinal studies involving large cohort of patients.

Consultative Interpretation for Lupus Anticoagulant by Expert Pathologist Reduces False-Positive Rates in the Era of Direct Oral Anticoagulants.

BACKGROUND: The diagnosis of antiphospholipid syndrome requires detection of antiphospholipid antibodies (aPL). A retrospective review of our testing practices revealed that societal recommendations for lupus anticoagulant (LA) testing as part of aPL testing are largely not followed by clinicians, and there was a high proportion of positive LA results. Increasing direct oral anticoagulant (DOAC) usage creates additional challenges in identifying LA. This prompted us to establish an order set with pathologist consultation ("LA panel") and testing algorithm to reduce false-positive LA and to ensure optimal LA identification and best practices for interpretation and follow-up. METHODS: The laboratory database was reviewed to determine the number of LA tests ordered and rate of LA positivity before and after the LA panel was instituted. We assessed the impact of pathologist consultation to minimize false-positive findings and on following diagnostic guidelines. RESULTS: LA panels were ordered for 1146 patients. LA was detected in 10% (111 of 1146) by dilute Russel viper venom time (dRVVT) normalized ratio [includes dRVVT screen (dRVVTs) positive/lupus-sensitive partial thromboplastin time (PTT-LA) positive and dRVVTs positive/PTT-LA negative] and 20% (228 of 1146) by Staclot-LA (includes dRVVTs negative/PTT-LA positive and dRVVTs positive/confirm negative). There was a reduction of false-positive LA by Staclot-LA; previously, 48% positive. We saw increased cancellation of LA testing for interfering anticoagulants [6.8% (16 of 236) vs 14.4% (55 of 383); P = 0.0061]. There was also increased adherence to follow-up LA testing [3% (8 of 236) vs 13.8% (53 of 383); P ≤ 0.001]. CONCLUSIONS: Creating a predetermined order set and testing algorithm with pathologist consultation improved LA testing interpretation and diagnostic follow-up testing.

Utilización de un dispositivo portátil para monitorear la relación internacional normalizada en pacientes con anticoagulante lúpico positivo / Use of a portable device to monitor the international normalized ratio in patients with positive lupus anticoagulant

La certeza del valor de la relación internacional normalizada (RIN), ensayo para controlar la anticoagulación con dicumarínicos, en pacientes con anticoagulante lúpico positivo (AL) es desconocida especialmente para los dispositivos al lado del paciente (POCT). El objetivo de este trabajo fue investigar si existe correlación entre el valor del RIN obtenido por el método tradicional y el obtenido con un dispositivo portátil en pacientes con AL positivo. Se estudiaron 35 pacientes anticoagulados por enfermedad tromboembólica con diagnóstico de AL positivo persistente a los que se les determinó al mismo tiempo el RIN por el método tradicional y con CoaguChek durante 4 controles consecutivos. El rango del RIN fue 1,9 a 5,60 y el RIN-POCT estuvo entre 2,0 y 4,92. La comparación del RIN vs RIN-POCT mostró r=0,98, pendiente: 1,56 (0,98-1,12) y una ordenada al origen de -0,088 (-0,282-0,007). El sesgo fue 2,1%. Para un nivel del RIN menor de 3,5 (n=136 controles) la diferencia del RIN promedio fue de 0,17 con un rango de 0,01-0,56. Un paciente, con triple positividad, mostró una diferencia entre ambos métodos mayor de 0,4 en dos controles. Para un RIN mayor de 4,5 el grado de concordancia fue menor pero no tiene implicancia clínica. Los resultados del RIN obtenidos por CoaguChek en los pacientes estudiados con AL positivo son útiles para la práctica clínica. Los datos obtenidos demuestran que hay una buena correlación entre el RIN tradicional y el CoaguChek. Por la gran diversidad de los equipos POCT los resultados no son extrapolables a otros dispositivos. Dada la heterogeneidad de los anticuerpos antifosfolípidos, es recomendable probar en cada paciente si hay una buena concordancia entre el RIN tradicional y el RIN-POCT.

The certainty of the value of the international normalized relation (INR) assay to control dicoumarin anticoagulation in patients with positive lupus anticoagulant (LA) is unknown especially for the point of care testing (POCT). The aim of this work was to investigate if there was a correlation between the INR values obtained by the traditional method and those obtained with a POCT in patients with positive LA. The population under study were 35 patients anticoagulated by thromboembolic disease with a persistent positive LA, whose INR was determined at the same time by the traditional method and with CoaguChek during 4 consecutive controls. The INR range was 1.9 to 5.60 and the RIN-POCT was between 2.0-4.92. The comparison of INR vs. INR - POCT showed r=0.98, slope: 1.56 (0.98-1.12) and ordered to the origin -0.088 (-0.282-0.007). The bias was 2.1%. For an INR level lower than 3.5 (n=136 controls) the average INR difference was 0.17 with a range of 0.01-0.56. One patient, with triple positivity showed a difference between both methods greater than 0.4. in two controls. For INR greater than 4.5, the degree of concordance is lower but has no clinical implications. The data obtained show that there is a good correlation between the traditional INR and the CoaguChek. The results of INR obtained by CoaguChek in patients studied with positive LA are useful for clinical practice. Due to the large diversity of POCT, the results cannot be extrapolated to other devices. Given the heterogeneity of antiphospholipid antibodies, it is advisable to test in each patient whether there is a good agreement between the traditional INR and INR-POCT.

A certeza do valor da razão internacional normalizada (RIN ou IIN), ensaio que controla a anticoagulação com dicumarínicos, em pacientes com anticoagulante lúpico positivo (AL) é desconhecida especialmente para os dispositivos de teste do tipo point-of-care (POCT). Este trabalho teve como objetivo pesquisar se existe correlação entre o valor de RIN obtido pelo método tradicional e aquele obtido com um dispositivo portátil em pacientes com AL positivo. Foram estudados 35 pacientes anticoagulados por doença tromboembólica com diagnóstico de AL positivo persistente aos quais lhes determinaram, ao mesmo tempo, a RIN pelo método tradicional e com CoaguChek durante 4 controles consecutivos. O intervalo de RIN foi de 1,9 a 5,60 e o de RIN-POCT ficou entre 2,0 e 4,92. A comparação de RIN vs RIN-POCT mostrou r=0,98, pendente: 1,56 (0,98-1,12) e uma ordenada à origem de -0,088 (-0,282-0,007). O viés foi 2,1%. Para um nível de RIN menor a 3,5 (n=136 controles) a diferença de RIN em média foi de 0,17 com um intervalo de 0,01-0,56. Um paciente, com tríplice positividade, mostrou uma diferença entre ambos os métodos maior a 0,4 em dois controles. Para um RIN de mais de 4,5, o grau de concordância foi menor, mas não tem consequências clínicas. Nos pacientes estudados com AL positivo, os resultados da RIN obtidos por CoaguChek são úteis para a prática clínica. Os dados obtidos demonstram que existe uma boa correlação entre a RIN tradicional e o CoaguChek. Devido à grande diversidade dos equipamentos POCT, os resultados não são extrapoláveis a outros dispositivos. É recomendável, visto a heterogeneidade dos anticorpos antifosfolípídes, provar em cada paciente a existência de uma boa concordância entre a RIN tradicional e a RIN-POCT.

The effect of DOAC-Stop on lupus anticoagulant testing in plasma samples of venous thromboembolism patients receiving direct oral anticoagulants.

Background Direct oral anticoagulants (DOACs) cause false positive lupus anticoagulant (LA) results. We assessed the impact of DOAC-Stop, reversing in vitro effects of DOACs, on LA testing in anticoagulated patients. Methods We assessed 75 venous thromboembolism patients aged 44.5±14.6 years. Blood samples were collected 2-28 h since intake of DOACs, including 50 patients on rivaroxaban, 20 on dabigatran and five on apixaban. LA testing was performed at baseline and after DOAC-Stop treatment. Positive LA was defined as the normalized (patient/standard plasma clotting time) LA screening and screening (LA1)/confirmation (LA2) ratios exceeding 1.2. Results LA diluted Russell's viper venom time (dRVVT) normalized screening test revealed abnormal results in 73 (97.3%) and activated partial thromboplastin time (APTT)-LA in 49 (65.3%) patients. In six (8%) patients, antiphospholipid syndrome (APS) was diagnosed. dRVVT LA1/LA2 was abnormal in 35 (50.7%) patients taking DOACs. The APTT ratio was normal in all studied subjects. DOAC-Stop completely removed dabigatran and reduced by 98% rivaroxaban and by 92.3% apixaban concentrations (all p<0.05). After DOAC-Stop screening dRVVT remained prolonged in 34 (49.3%) patients (p<0.001), while dRVVT LA1/LA2 was abnormal in six (8.7%) subjects, with no association with DOAC concentrations at baseline and after DOAC-Stop. The APTT-LA screening test remained prolonged in five (7.2%) patients, while the APTT LA1/LA2 ratio was normal in those subjects. DOAC-Stop did not influence LA testing in APS patients. Conclusions Application of DOAC-Stop effectively reduced plasma DOAC concentrations leading to appropriate dRVVT results in up to 97% of VTE patients.

Laboratory Diagnostics in Thrombophilia.

A thrombophilic disorder is a hereditary or acquired condition that increases the risk of thrombosis. The most common hereditary thrombophilias that predispose to venous thrombosis in the Caucasian population are the heterozygous forms of the factor V Leiden and prothrombin G20210A mutation that are generally detected by direct DNA genotyping. Immunologic antigen assays and chromogenic or clot-based activity assays are used to identify deficiencies in the natural coagulation inhibitors antithrombin, protein C and protein S. Because pre-analytical errors and acquired causes of low antithrombin, protein C or protein S levels are considerably more common than hereditary deficiencies, all potential conditions that may lower activity levels of the natural coagulation inhibitors (e.g. concomitant liver disease, pregnancy, anticoagulant therapy) must be considered and excluded before the diagnosis of an inhibitor deficiency can be made. To avoid misclassification, the diagnosis should not be made based on a single abnormal test result. Thus, repetitive testing when the patient is not on anticoagulant therapy is mandatory to confirm the diagnosis. Screening for antiphospholipid syndrome (APS) comprises testing for lupus anticoagulants (LAs) and the presence of IgG or IgM antibodies directed against phospholipids and phospholipid-binding proteins such as ß-2-glycoprotein-I. A combination of clot-based assays has been recommended to demonstrate LA activity, whereas solid-phase immunoassays allow the detection of anti-cardiolipin and anti-ß-2-glycoprotein-I antibodies. The diagnosis of APS requires the persistence of antiphospholipid antibodies for at least 12 weeks together with thrombotic and/or obstetric features of APS.

Laboratory testing for lupus anticoagulant (LA) in patients taking direct oral anticoagulants (DOACs): potential for false positives and false negatives.

We and others have previously highlighted the potential problems with testing of lupus anticoagulants (LA) in patients on anticoagulant therapy, including most recently as related to the direct oral anticoagulants (DOACs). Thus, current DOACs in use (e.g., dabigatran, a direct thrombin inhibitor, and apixaban and rivaroxaban, both direct Xa inhibitors), affect a wide variety of coagulation assays, including those used in LA investigation. The Russell viper venom time (RVVT) assay in particular, key to the investigation of LA, is highly sensitive to DOACs. LA is a marker of thrombophilia, and patients who have had a thrombosis may be placed on a DOAC. Thus, there is a high likelihood that LA testing will be requested on patients whilst they are on DOACs. In the current report, we have assessed data from our facility for the past two and a half years for all LA tests performed by RVVT testing, and have evaluated this data with respect to patient anticoagulant status. In total, there were 7170 test requests for RVVT associated testing during the period of data capture. Most LA-RVVT screen results (5008; ∼70%) were within normal limits, thereby excluding LA by RVVT method in most of the patient cohort. All DOACs led to a prolongation in both RVVT screen and confirm assays. However, rivaroxaban affected the screen more than the confirm, leading to higher RVVT ratios, whereas apixaban affected the confirm more than the screen, leading to lower RVVT ratios. LA testing in the presence of DOACs also led to lower intra-patient consistency in LA test results. We conclude that ex-vivo data appears to confirm the potential for false positive (with rivaroxaban) and potential for false negative (with apixaban) identification of LA in patients on DOAC treatment. We also make some recommendations in regards to such testing.

Dilute Russell viper venom time interpretation and clinical correlation: A two-year retrospective institutional review.

INTRODUCTION: The dilute Russell viper venom time (dRVVT) detects lupus anticoagulant (LA). International Society for Thrombosis and Haemostasis (ISTH) guidelines specify positivity criteria, which differ from the assay manufacturer's criteria. METHODS: Two years of dRVVT testing at our institution were reviewed. For patients with prolonged dRVVT screening times, we evaluated dRVVT results by ISTH and manufacturer's criteria and correlated with the results of other antiphospholipid syndrome (APS) testing (LA-sensitive activated partial thromboplastin time and antiphospholipid antibodies) and with history of thromboembolism and other APS manifestations. RESULTS: Approximately one-fifth of dRVVTs exhibited a prolonged screening time. Among first prolonged dRVVTs, 35% were positive by both ISTH and manufacturer criteria, 44% met neither criteria, and 20% were equivocal (positive by only ISTH or manufacturer). Positivity by ISTH guidelines alone correlated better with other positive APS tests than manufacturer criteria positivity. Positive dRVVTs by both criteria correlated even more strongly with other positive APS assays. We investigated the likelihood of eventual APS diagnosis depending on the testing indication. No patient tested for LA solely for prolonged screening aPTT was subsequently diagnosed with APS. In patients with thrombosis, prolonged dRVVT clotting time not meeting both ISTH and manufacturer criteria was rarely associated with eventual APS diagnosis. CONCLUSION: We examined the correlation of dRVVT results with other APS testing and clinical outcomes. Interpretation method impacted how dRVVT results related to other APS testing, and, in limited data, to clinical findings. Patients with prolonged dRVVTs meeting only one set of positivity criteria rarely received an APS diagnosis.

Lupus anticoagulant identifies two distinct groups of patients with different antibody patterns.

BACKGROUND: Whether antibodies directed to ß2-Glycoprotein I (aß2GPI) are responsible for LA activity is not well defined. However, in the absence of such antibodies the molecule responsible for LA phenomenon is unknown. OBJECTIVE: The aim of this study was the biochemical identification of the target antigen epitope of aPL responsible of LA activity in the absence of aß2GPI antibodies together with the biological and clinical characteristics of these patients in comparison with classical triple positive patients. PATIENTS/METHODS: A comparison of patients with LA without (LA+/aß2GPI-) and those with (LA+/aß2GPI+) associated aß2GPI antibodies was performed. Size exclusion chromatography and analytical chromatography were used to identify the molecule with LA activity in patients LA+/aß2GPI-. RESULTS AND CONCLUSIONS: Analytical size-exclusion chromatography revealed a peak of 996Kd with LA activity perfectly overlapping that of IgM anti phosphatidylserine/prothrombin (aPS/PT) antibodies. Similarly, all the 25 LA+/aß2GPI- patients were positive for aPS/PT antibodies. LA+/aß2GPI- compared to 33 LA+/aß2GPI+ patients turned out to be significantly older, with a lower rate of previous thromboembolic events and a weaker LA activity. Search for aPS/PT and aß2GPI antibodies in patients with LA is useful to identify two subgroups of LA at different risk of thromboembolic events.

Una reflexión sobre el anticoagulante lúpico: cómo lo definimos, determinamos e interpretamos / A reflection on how we define, determine and interpret the finding of lupus anticoagulant

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Systemic lupus erythematosus with inflammatory bowel disease-ulcerative colitis: case report.

A 30-year-old female presented to the rheumatology outpatient clinic of the Internal Medicine Department, Ain Shams University Hospital, Cairo, Egypt, complaining of a large right leg ulcer consistent with pyoderma gangrenosum. There was history of recurrent attacks of bleeding per rectum of one-year duration. During hospitalization she noticed blurring of vision in the left eye with diffuse blackish discoloration of the feet and toes, consistent with small-vessel vasculitis. Colonoscopy with biopsy and histopathology confirmed the diagnosis of inflammatory bowel disease-ulcerative colitis (IBD-UC). Meanwhile, the patient fulfilled the SLICC classification criteria for systemic lupus erythematosus (SLE): recurrent oral ulcers, positive antinuclear antibody testing, proteinuria >0.5 gm/24-hour urine, positive test for lupus anticoagulant and consumed C3 complement component. Herein we report a rare case of coexistence of SLE and IBD-UC.

Antiphospholipid syndrome and recurrent miscarriage: A systematic review and meta-analysis.

Antiphospholipid syndrome (APS) is an autoimmune condition that is associated with thrombosis and morbidity in pregnancy. The exact mechanisms by which these associations occur appear to be heterogeneous and are not yet well understood. The aim of this study was to identify and analyze publications in recent years to better understand the diagnosis and its contribution to monitoring APS among women with recurrent miscarriage (RM). This systematic review and meta-analysis was conducted using the PubMed and Web of Knowledge databases, with articles published between 2010 and 2014, according to the PRISMA statement. Of the 85 identified studies, nine were selected. Most of the studies reported an association between recurrent miscarriage and specific antiphospholipid antibodies, as anticardiolipin antibodies (aCL), lupus anticoagulant (LA), anti-ß2-glycoprotein I antibodies (aß2GPI) and antiphosphatidylserine (aPS), which showed a relationship with RM. The main result of the meta-analysis revealed association between antiphospholipid antibodies (aPLs) and/or APS compared to the patients with RM (OR: 0.279; 95% CI: 0.212-0.366) and APS cases compared to the patients with RM (OR: 0.083; 95% CI: 0.036-0.189). High heterogeneity among these studies (I2=100.0%, p <0.001) was observed. In addition, there was no significant publication bias across studies according to Begg's test (p=0.230), although Egger's test (p=0.037) suggests significant publication bias. The funnel plot was slightly asymmetrical. Systematic review and meta-analysis demonstrated a positive association between antiphospholipid antibodies and/or antiphospholipid syndrome in patients with recurrent miscarriage.

Novel diagnostic and therapeutic frontiers in thrombotic anti-phospholipid syndrome.

The anti-phospholipid syndrome (APS) is an autoimmune disorder characterized by vascular thrombosis and/or pregnancy morbidity, associated with a persistent positivity for anti-phospholipid antibodies (aPL). The current classification criteria for APS include three laboratory tests: lupus anti-coagulant (LA), anti-cardiolipin (aCL), and anti-ß2 glycoprotein-I (ß2GPI). To date, the therapeutic approach for thrombotic APS mainly centers on long-term anti-coagulation with a vitamin K antagonist (VKA). APS management may represent a challenge for the treating physicians. Patients with different aPL profiles need a tailored risk-stratified approach. Moreover, in patients with recurrent thrombotic events despite therapy with VKA, or in those with microvascular involvement, new therapeutic options are highly needed. In this review, we aim to elucidate recent findings about new aPL specifities, available risk scoring models, and novel therapeutic approaches in APS management.

Lupus anticoagulant-hypoprothrombinemia syndrome presenting with co-existing cerebral venous thrombosis and subdural hemorrhage.

The lupus anticoagulant-hypoprothrombinemia syndrome (LA-HPS) - the association of acquired factor II deficiency and lupus anticoagulant - is a rare disease that may cause a predisposition not only to thrombosis but also to severe bleeding. We are reporting on a 36-year-old female patient presenting with co-existing cerebral venous thrombosis and subdural hemorrhage. The coagulation screening showed a prolonged prothrombin time (PT), activated partial thromboplastin time (aPTT), and a normal fibrinogen level and platelet count. Evaluation of the clotting factors revealed decreased levels of factors II (37%). Factors V, VIII, IX and XI were normal. Lupus anticoagulant (LA) was demonstrated by the Dilute Russell's Viper Venom Test (DRVVT). Immunological work-up was positive for IgG type anticardiolipines antibodies (aCL). Successful management consisted first of oral prednisone (60mg/d). Thus, anticoagulation was introduced once factor II had stabilized.

Diagnóstico en el síndrome antifosfolipídico: desde una perspectiva histórica a la aparición de nuevos autoanticuerpos / Diagnosis of antiphospholipid syndrome: From an historical perspective to the emergence of new autoantibodies

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Síndrome de anticoagulante lúpico-hipoprotrombinemia: una extraña asociación en el lupus eritematoso sistémico / Lupus anticoagulant-hypoprothrombinemia syndrome: A rare association in systemic lupus erythematosus

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Síndrome de anticuerpos antifosfolípidos: más de 30 años mejorando los protocolos diagnósticos y terapéuticos / No disponible

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