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Connective tissue disease
Published in Catherine Nelson-Piercy, Handbook of Obstetric Medicine, 2020
LA is a misnomer coined because it prolongs coagulation times in vitro. It is detected by the prolongation of the activated partial thromboplastin time or the dilute Russell's viper venom time (dRVVT). This prolongation fails to correct with the addition of platelet poor plasma, but corrects with excess phospholipid.
Lupus Anticoagulants: Characteristics, Methods of Laboratory Detection and Some Clinical Associations
Published in E. Nigel Harris, Thomas Exner, Graham R. V. Hughes, Ronald A. Asherson, Phospholipid-Binding Antibodies, 2020
Thomas Exner, Douglas Triplett
The regular DRVVT is carried out by preincubating test plasma (0.1 ml) with 0.1 ml of diluted Russell’s viper venom (approximately 5 x 10~5% w/v, Wellcome reagents U.K. or Sigma chemicals U.S. in 0.02 M tris pH 7.5, 0.15 M sodium chloride) and 0.1 ml of diluted phospholipid (Thrombofax, Ortho Diagnostics diluted 1:8 in tris-buffered saline was originally used, but alternatives with similar platelet factor 3 activity can be used) for 30s at 37°C. The time from the addition of 0.1 ml of 0.03 M calcium chloride to a clotting end point is then accurately determined either visually (tilt-tube) or by Fibrometer or a similar machine. The normal range is approximately 25 to 30 s.49
Case 98
Published in Atul B. Mehta, Keith Gomez, Clinical Haematology, 2017
A 32-year-old woman is admitted with severe headache and vomiting that has gradually been getting worse over the previous week. She has no significant past medical history and she is otherwise fit and well. A magnetic resonance imaging (MRI) scan shows cerebral venous sinus thrombosis. There is no family history of thrombosis and there are no obvious provoking factors. She completes 6 months of anti-coagulation with warfarin. She is now asymptomatic and a repeat MRI scan shows residual thrombus although the overall size has reduced. A thrombophilia screen is carried out and shows a weakly positive dilute Russell viper venom time (DRVVT). Three months later, the DRVVT is still weakly positive and tests for anti-cardiolipin and anti-β2 glycoprotein 1 antibodies are negative.
Autoantibodies in association with subchorionic haematoma in early pregnancy
Published in Annals of Medicine, 2021
Yang Li, Ensheng Wang, Shisi Huang, Changling Zhu, Kemei Zhang, Jiaou Zhang, Haiyan Xu, Jing Shu
All the recruited patients took non-fasting venous blood tests of immune indexes in their early pregnancy periods. The test items included antinuclear antibodies (ANAs), anticardiolipin antibody (ACL), anti-β2 glycoprotein1 (anti-β2GP1) antibody, lupus anticoagulant (LA) and so on. Antinuclear antibodies were tested with an indirect fluorescent antibody method using test kits supplied by EUROIMMUN (Hangzhou) Medical Laboratory Diagnosis Co., Ltd., China. Serum fluorescence titre ≥ 1:100 was considered positive. Anticardiolipin antibodies were tested with a standardized enzyme linked immunosorbent assay (ELISA). Reagents were supplied by Shenzhen SCIARRAY Biotechnology Co., Ltd., China. ACL-IgG/IgM > 12 GPL/MPL was considered positive. Anti-β2GP1 antibodies were analysed using ELISA with test kits supplied by Guangzhou Kangrun Biological Technology Co., Ltd., China. A titre > 20 U/ml was considered positive. The definition of a moderate-to-high titre of ACL or anti-β2GP1 was 40 or more GPL or MPL units (>99th percentile). Lupus anticoagulant was tested with HemosIL dRVVT Screen and dRVVT Confirm assays from Instrumentation Laboratory Co., USA. Results of screen and confirm assays were expressed as ratios of patient to reference plasma clotting times. Confirm assay was realised when screen ratio was equal or above the cut-off value. The cut-off values for the screen and normalised ratios were 1.20.
Effects of the oral, direct factor Xa inhibitor edoxaban on routine coagulation assays, lupus anticoagulant and anti-Xa assays
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 2018
Andreas Hillarp, Karin Strandberg, Fariba Baghaei, Inger Fagerberg Blixter, Kerstin M. Gustafsson, Tomas L. Lindahl
Lupus anticoagulant testing was performed with two integrated assays based on a screen reagent and a confirm reagent that utilizes the dilute Russell’s viper venom time (dRVVT) test. One test, Technoclot LA Screen and Technoclot LA Confirm (Technoclone Gmbh, Vienna, Austria) was performed on the BCS-XCP and the other test, STA-Staclot DRVV Screen and STA-Staclot DRVV Confirm from Stago was performed on the STAR Max instrument (Stago, Asnieres, France). Both tests were performed according to the manufacturer’s instructions. A ratio between screen and confirm assays of 1.2 and 1.5 was considered weakly positive or border line, a ratio between 1.5 and 2.0 was classified as moderately positive, and a ratio above 2.0 indicated a strongly positive result as previously described [20].
Clinical feature and anti-phospholipid antibody profiles of pregnancy failure in young women with antiphospholipid antibody syndrome treated with conventional therapy
Published in Modern Rheumatology, 2018
Kayoko Kaneko, Shuko Mishima, Mikako Goto, Mari Mitsui, Shinji Tanigaki, Kenji Oku, Nobuaki Ozawa, Eisuke Inoue, Tatsuya Atsumi, Haruhiko Sago, Atsuko Murashima
Two clotting tests were performed for LA determination, using a semiautomated hemostasis analyzer (Start 4; Diagnostica Stago, Asnieres, France) according to the guidelines recommended by the Subcommittee on LA/Antiphospholipid Antibody of the Scientific and Standardisation Committee of the International Society on Thrombosis and Hemostasis [12]. For measurement of the activated partial thromboplastin time (aPTT), a sensitive reagent with a low phospholipid concentration (PTT-LA test; Diagnostica Stago) was used for screening and mixing test, and the results were confirmed with the use of a StaClot LA kit (Diagnostica Stago). The dilute Russell’s viper venom time (dRVVT) was used to screen for the presence of LA, and the results were confirmed with a Gradipore LA test. The cutoff level of positivity for the LA test was previously established as above the 99th percentile of levels in 40 healthy subjects, as used for routine assays described before [13].