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Shimomura D, Kumano O, Ueda K, Kitano K, Arai N, Shimada M, Kamioka M. New method to differentiate between lupus anticoagulants, progressive coagulation inhibitors and coagulation factor deficiencies in the mixing tests. Int J Lab Hematol 2024. [PMID: 38644054 DOI: 10.1111/ijlh.14289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Accepted: 04/05/2024] [Indexed: 04/23/2024]
Abstract
INTRODUCTION Mixing tests in activated partial thromboplastin time (APTT) are used for the differentiation between lupus anticoagulants (LA), coagulation inhibitors, and factor deficient samples with APTT prolongation. However, the indexes for the differentiation have not been established. The present study aimed to develop new mixing test indexes for the differentiation. METHODS Twenty-six LA-positive, 8 progressive coagulation factor VIII inhibitor, and 35 coagulation deficient samples were employed. APTT were measured for normal plasma, patient plasma, and mixing plasma prepared at a ratio of 1:1 proportion in both without incubation and 2 h-incubation. New two parameters named as ALD50 and mixture plasma-patient plasma after Warming change rate Subtraction (WaS) calculated from the clotting times of normal, 1:1 mixing and patient samples with/without 2 h-incubation were established. In the samples with WaS result of <10.2%, ALD50 of ≥87.8%, and < 87.8% were defined as LA and coagulation factor deficiency, respectively, and WaS of ≥10.2% defined progressive coagulation factor inhibitors. RESULTS Sensitivity and specificity to LA were 80.8% and 93.0% for ALD50, and sensitivity and specificity to progressive coagulation factor inhibitor were 100.0% and 100.0% for WaS, respectively. The agreement between sample classification and WaS-ALD50 was 88.4% (61/69). CONCLUSIONS ALD50 and WaS showed acceptable sensitivity and specificity to LA and progressive coagulation factor inhibitor, respectively. These indexes would be useful for the differentiation between LA, factor deficiency, and progressive coagulation factor inhibitor in the mixing tests.
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Affiliation(s)
- Daiki Shimomura
- Department of Laboratory Medicine, Tenri Hospital, Tenri, Japan
| | - Osamu Kumano
- Protein technology, Department of Reagent engineering, Sysmex Corporation, Kobe, Japan
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Takamatsu, Japan
| | - Kaori Ueda
- Osaka Branch, Sysmex Corporation, Osaka, Japan
| | - Keisuke Kitano
- Protein technology, Department of Reagent engineering, Sysmex Corporation, Kobe, Japan
| | - Nobuo Arai
- Protein technology, Department of Reagent engineering, Sysmex Corporation, Kobe, Japan
| | - Masashi Shimada
- Department of Laboratory Medicine, Tenri Hospital, Tenri, Japan
| | - Mikio Kamioka
- Department of Laboratory Medicine, Tenri Hospital, Tenri, Japan
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Apipongrat D, Lamool R, Arnutti P, Ruangpratheep C, Chantkran W. Comparison of different algorithms for lupus anticoagulant detection: a single-center experience. Res Pract Thromb Haemost 2024; 8:102333. [PMID: 38404944 PMCID: PMC10885790 DOI: 10.1016/j.rpth.2024.102333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 01/06/2024] [Accepted: 01/08/2024] [Indexed: 02/27/2024] Open
Abstract
Background The laboratory tests for lupus anticoagulant (LA) detection comprise complex and multistep coagulation testing procedures. There is no established gold standard assay or direct comparison of algorithms as recommended by different guidelines. Objectives This study aimed to evaluate and compare the LA detection performance of different laboratory algorithms suggested by the existing guidelines. Methods The routine LA test data of 1801 plasma samples, including 188 LA-positive and 1613 LA-negative samples, were re-evaluated by applying the algorithms recommended by existing guidelines and were interpreted using various methods. Diagnostic performance indices for each LA detection algorithm were compared with those of the other algorithms. The efficacies of the different interpretation methods were analyzed to determine a suitable interpretation methodology for each assay. Results The diagnostic performance for detecting LA varied by the algorithm and method of interpretation used. All laboratory algorithms displayed exceptional diagnostic performance with all diagnostic parameters of >90.0%. Nearly perfect agreement was observed in all algorithms when compared to the Clinical and Laboratory Standards Institute 2014 guideline interpreted by normalized screen-to-confirm ratio (NSCR) and mixing test-specific cutoff (MTC), as a reference assay (Cohen's kappa coefficient, >0.90 [range, 0.94-1.00]). A combination of the index of circulating anticoagulant and NSCR was optimal for interpreting the activated partial thromboplastin time-based test, whereas a combination of the MTC and NSCR was suitable for the diluted Russell's viper venom time-based test. Conclusion All laboratory algorithms showed equivalent diagnostic performance. Establishing the best method of interpretation for each assay is recommended to improve LA detection performance.
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Affiliation(s)
- Dollapak Apipongrat
- Division of Hematology, Department of Medicine, Phramongkutklao Hospital, Bangkok, Thailand
| | - Rattapan Lamool
- Division of Hematology, Department of Medicine, Phramongkutklao Hospital, Bangkok, Thailand
| | - Pasra Arnutti
- Department of Biochemistry, Phramongkutklao College of Medicine, Bangkok, Thailand
| | | | - Wittawat Chantkran
- Department of Pathology, Phramongkutklao College of Medicine, Bangkok, Thailand
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3
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Kumano O, Moore GW. Validation of mixing test-specific cut-off in lupus anticoagulant mixing test interpretation for multiple reagents. Thromb Res 2023; 231:39-43. [PMID: 37801773 DOI: 10.1016/j.thromres.2023.09.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 08/30/2023] [Accepted: 09/26/2023] [Indexed: 10/08/2023]
Affiliation(s)
- Osamu Kumano
- Research Department, Hyphen BioMed, Neuville sur Oise, France; Sysmex Corporation, Kobe, Japan; Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Takamatsu, Japan.
| | - Gary W Moore
- Department of Haematology, Specialist Haemostasis Unit, Addenbrooke's Hospital, Cambridge, UK; Department of Natural Sciences, Middlesex University, London, UK; Department of Haemostasis and Thrombosis, Viapath Analytics, St. Thomas' Hospital, London, UK
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4
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Molinari AC, Martini T, Banov L, Ierardi A, Leotta M, Strangio A, Santoro RC. Lupus Anticoagulant Detection under the Magnifying Glass. J Clin Med 2023; 12:6654. [PMID: 37892792 PMCID: PMC10607820 DOI: 10.3390/jcm12206654] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023] Open
Abstract
Diagnosis of antiphospholipid syndrome (APS) requires the presence of a clinical criterion (thrombosis and/or pregnancy morbidity), combined with persistently circulating antiphospholipid antibodies (aPL). Lupus anticoagulant (LA) is one of the three laboratory parameters (the others being antibodies to either cardiolipin or β2-glycoprotein I) that defines this rare but potentially devastating condition. For the search for aCL and aβ2-GP-I, traditionally measured with immunological solid-phase assays (ELISA), several different assays and detection techniques are currently available, thus making these tests relatively reliable and widespread. On the other hand, LA detection is based on functional coagulation procedures that are characterized by poor standardization, difficulties in interpreting the results, and interference by several drugs commonly used in the clinical settings in which LA search is appropriate. This article aims to review the current state of the art and the challenges that clinicians and laboratories incur in the detection of LA.
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Affiliation(s)
- Angelo Claudio Molinari
- Thrombosis and Hemostasis Unit, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy; (A.C.M.); (L.B.)
| | - Tiziano Martini
- Immuno-Haematology and Transfusion Medicine, Center for Congenital Bleeding Disorders, Cesena General Hospital, 47521 Cesena, Italy
| | - Laura Banov
- Thrombosis and Hemostasis Unit, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy; (A.C.M.); (L.B.)
| | - Antonella Ierardi
- Hemostasis and Thrombosis Unit, Azienda Ospedaliero Universitaria Dulbecco, 88100 Catanzaro, Italy; (A.I.); (M.L.); (A.S.); (R.C.S.)
| | - Marzia Leotta
- Hemostasis and Thrombosis Unit, Azienda Ospedaliero Universitaria Dulbecco, 88100 Catanzaro, Italy; (A.I.); (M.L.); (A.S.); (R.C.S.)
| | - Alessandra Strangio
- Hemostasis and Thrombosis Unit, Azienda Ospedaliero Universitaria Dulbecco, 88100 Catanzaro, Italy; (A.I.); (M.L.); (A.S.); (R.C.S.)
| | - Rita Carlotta Santoro
- Hemostasis and Thrombosis Unit, Azienda Ospedaliero Universitaria Dulbecco, 88100 Catanzaro, Italy; (A.I.); (M.L.); (A.S.); (R.C.S.)
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Adcock DM, Moore GW, Montalvão SDL, Kershaw G, Gosselin RC. Activated Partial Thromboplastin Time and Prothrombin Time Mixing Studies: Current State of the Art. Semin Thromb Hemost 2023; 49:571-579. [PMID: 36055261 DOI: 10.1055/s-0042-1756196] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Mixing studies have long been in the clinical laboratory armamentarium for investigating unexpected, prolonged activated partial thromboplastin time (aPTT) or prothrombin time (PT). The purpose of the mixing study is to identify whether the aPTT/PT prolongation is secondary to a factor deficiency versus an inhibitor, which would present as a "corrected" and "noncorrected" mixing study, respectively. The differentiation between a factor deficiency and inhibitor may likely further direct clinical decisions, including additional diagnostic testing or factor replacement therapy. While aPTT/PT mixing studies are simple tests to perform, there is a lack of standardization for both the testing protocol and the interpretation of what is considered to be a corrected or noncorrected mixing study result. This review will describe the common indications for the mixing test, preanalytic variables that may affect mixing study performance, and describe several methods for interpreting the results of aPTT and PT mixing tests.
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Affiliation(s)
| | - Gary W Moore
- Specialist Haemostasis Unit, Department of Haematology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom
- Department of Natural Sciences, Middlesex University London, London, United Kingdom
| | - Silmara de Lima Montalvão
- Laboratory Hemostasis, Hematology and Hemotherapy Center, University of Campinas (UNICAMP), Campinas-SP, Brazil
| | - Geoffrey Kershaw
- Institute of Haematology, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
| | - Robert C Gosselin
- Davis Health System, Hemostasis and Thrombosis Center, University of California, Sacramento, California
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Cabo J, Morimont L, Baudar J, Guldenpfennig M, Jacqmin H, Soleimani R, Lecompte T, Douxfils J, Mullier F. Variability among commercial batches of normal pooled plasma in lupus anticoagulant testing. Int J Lab Hematol 2023; 45:126-136. [PMID: 36222181 DOI: 10.1111/ijlh.13977] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 09/15/2022] [Indexed: 01/18/2023]
Abstract
INTRODUCTION Lupus anticoagulant (LA) testing requires normal pooled plasma (NPP) in performing mixing studies and can be used for normalized ratios of clotting times (CTs). The aims were to demonstrate whether significant differences in clotting times between two batches of a same commercial NPP (CRYOcheck™) directly affect NPP-based cut-off values. METHODS Diluted Russell Viper venom time (DRVVT) and activated partial thromboplastin time (aPTT) were used for LA testing. Screening, mixing and confirm tests were performed with Stago® instruments and reagents. Two batches of commercial NPP (A1291 and A1301 from CRYOcheck™; frozen) were compared in the determination of cut-off values. Cut-off values were defined as 99th percentile values of 60 healthy donors and compared with Mann-Whitney U test. RESULTS Cut-off values obtained with the two NPP batches were significantly different for DRVVT (screen normalized ratio: 1.09 vs. 1.24, screen mix: 41.9 s vs. 38.9 s; index of circulating anticoagulant: 5.0 vs. 8.4; all had p-value <.001). On the contrary, no significant differences were observed for aPTT (screen normalized ratio: 1.32 vs. 1.34; p-value = .4068, screen mix: 37.8 s vs. 38.1 s; p-value = .1153) except for index of circulating anticoagulant: 9.6 versus 10.4 (p-value <.05). CONCLUSION This study demonstrates that differences between two commercial NPP batches produced by a same manufacturer influenced LA cut-off values used for mixing studies and normalized ratios. Adequate cut-off setting, taking into account NPP CTs, is important to provide accurate conclusion about the presence or absence of a LA and avoid potential clinical impact.
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Affiliation(s)
- Julien Cabo
- CHU UCL Namur, Namur Thrombosis and Hemostasis Center (NTHC), Université catholique de Louvain, Yvoir, Belgium
| | - Laure Morimont
- Département de pharmacie, Namur Thrombosis and Hemostasis Center (NTHC), Université de Namur, Namur, Belgium.,Qualiblood s.a., Namur, Belgium.,Department of Pharmacy, Namur Thrombosis and Hemostasis Center (NTHC), Namur Research Institute for Life Sciences (NARILIS), Université de Namur, Namur, Belgium
| | - Justine Baudar
- CHU UCL Namur, Namur Thrombosis and Hemostasis Center (NTHC), Université catholique de Louvain, Yvoir, Belgium
| | - Maité Guldenpfennig
- CHU UCL Namur, Namur Thrombosis and Hemostasis Center (NTHC), Université catholique de Louvain, Yvoir, Belgium
| | - Hugues Jacqmin
- CHU UCL Namur, Namur Thrombosis and Hemostasis Center (NTHC), Université catholique de Louvain, Yvoir, Belgium
| | - Reza Soleimani
- CHU UCL Namur, Namur Thrombosis and Hemostasis Center (NTHC), Université catholique de Louvain, Yvoir, Belgium
| | - Thomas Lecompte
- Department of Pharmacy, Namur Thrombosis and Hemostasis Center (NTHC), Namur Research Institute for Life Sciences (NARILIS), Université de Namur, Namur, Belgium.,Vascular Medicine Division and Regional Competence Centre for Rare Vascular and Systemic Autoimmune Diseases, Université de Lorraine, Nancy, France
| | - Jonathan Douxfils
- Département de pharmacie, Namur Thrombosis and Hemostasis Center (NTHC), Université de Namur, Namur, Belgium.,Qualiblood s.a., Namur, Belgium.,Department of Pharmacy, Namur Thrombosis and Hemostasis Center (NTHC), Namur Research Institute for Life Sciences (NARILIS), Université de Namur, Namur, Belgium
| | - François Mullier
- CHU UCL Namur, Namur Thrombosis and Hemostasis Center (NTHC), Université catholique de Louvain, Yvoir, Belgium.,Department of Pharmacy, Namur Thrombosis and Hemostasis Center (NTHC), Namur Research Institute for Life Sciences (NARILIS), Université de Namur, Namur, Belgium
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7
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Matsuda M, Hoshiyama Y, Ogawa K, Emmi M, Terai S, Moriyama M. Performance characteristics of 5 numerical indexes in mixing test interpretation under coexistence of lupus anticoagulant and coagulation factor deficiency. Res Pract Thromb Haemost 2023; 7:100065. [PMID: 36891278 PMCID: PMC9986643 DOI: 10.1016/j.rpth.2023.100065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 01/12/2023] [Accepted: 01/14/2023] [Indexed: 02/05/2023] Open
Abstract
Background The mixing test is useful to investigate the cause of unexpectedly prolonged activated partial thromboplastin time (APTT). Several indexes are available for distinguishing correction from non-correction (ie, factor deficiency from inhibitors), but their performance characteristics may differ because of their different formulas. Furthermore, it is unclear how each index performs under the coexistence of factor deficiency and inhibitors. Objectives The objective of this study was to examine the differences in indexes, depending on factor VIII activity (FVIII:C) levels and lupus anticoagulant (LA) titers in test samples. Methods APTT was measured in spiked samples with various FVIII:C levels and LA titers, normal pooled plasma (NPP), and their 4:1, 1:1, and 1:4 mixtures. The following 5 indexes were calculated: index of circulating anticoagulant, mixing test normalized ratio, 4:1 and 1:1 percent corrections, and an APTT difference between the 1:1 mixture and NPP. The samples with LA, showing correction, were measured for FVIII:C in a one-stage assay to check parallelism. Results All indexes showed correction under FVIII deficiency and non-correction under higher LA titers. However, under lower LA titers, some indexes showed non-correction but others showed correction because of dilution effects and variations in formulas and/or sample mix ratios. The differences among the indexes were more pronounced under coexistent FVIII deficiency and LA, even though LA titers were equal in the tested samples; samples with lower FVIII:C showed correction, whereas those with normal FVIII:C showed non-correction. The samples tested for FVIII:C showed non-parallelism. Conclusion Each index had different performance characteristics to LA samples, which were pronounced under low FVIII:C levels in test samples.
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Affiliation(s)
- Masato Matsuda
- Department of Clinical Laboratory Sciences, School of Health Sciences, Fukushima Medical University, Fukushima, Japan.,Division of Gastroenterology and Hepatology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.,Medical Laboratory Division, Niigata University Medical and Dental Hospital, Niigata, Japan
| | - Yoshiki Hoshiyama
- Medical Laboratory Division, Niigata University Medical and Dental Hospital, Niigata, Japan
| | - Kazuei Ogawa
- Department of Clinical Laboratory Sciences, School of Health Sciences, Fukushima Medical University, Fukushima, Japan
| | - Mari Emmi
- Product Strategy Department, Diagnostics Division, SEKISUI MEDICAL Co. Ltd., Tokyo, Japan
| | - Shuji Terai
- Division of Gastroenterology and Hepatology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.,Medical Laboratory Division, Niigata University Medical and Dental Hospital, Niigata, Japan
| | - Masato Moriyama
- Department of Medical Oncology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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8
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Moore GW. Lupus Anticoagulant Testing: Dilute Prothrombin Time (dPT). Methods Mol Biol 2023; 2663:275-288. [PMID: 37204717 DOI: 10.1007/978-1-0716-3175-1_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Lupus anticoagulants (LA) rarely affect routine prothrombin time assays because the high phospholipid (PL) content in thromboplastin reagents tends to overwhelm the antibodies. Dilution of thromboplastin to create a dilute prothrombin time (dPT) screening test renders the assay sensitive to the presence of LA. Technical and diagnostic performances are enhanced if recombinant thromboplastins are employed in place of tissue-derived reagents. Presence of an LA cannot be deduced from an elevated screening test alone since other coagulation disturbances can prolong clotting times. Confirmatory testing with less dilute or undiluted thromboplastin reveals the PL-dependent nature of LA by reducing the clotting time relative to that of the screening test. Where appropriate, such as a known or suspected coagulation factor deficiency, mixing tests are valuable in correcting factor deficiencies and evidencing inhibitory properties of LA, to increase diagnostic specificity. Although LA testing is commonly restricted to dilute Russell's viper venom time and activated partial thromboplastin time, dPT is sensitive to LA unreactive in those assays, and inclusion in routine testing increases detection rates of clinically significant antibodies.
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Affiliation(s)
- Gary W Moore
- Research and Development, Technoclone Herstellung von Diagnostika und Arzneimitteln GmbH, Vienna, Austria.
- Specialist Haemostasis Unit, Department of Haematology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
- Department of Natural Sciences, Faculty of Science and Technology, Middlesex University London, London, UK.
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Abstract
Lupus anticoagulant (LA) is one of the three criteria antiphospholipid antibodies (aPLs) employed in classification, and by default diagnosis, of antiphospholipid syndrome (APS). Detection of LA is not via calibrated assays but is based on functional behavior of the antibodies in a medley of coagulation assays. A prolonged clotting time in a screening test is followed by demonstration of phospholipid dependence and inhibitory properties in confirmatory and mixing tests, respectively, which are modifications of the parent screening test. Complications arise because no single screening test is sensitive to every LA, and no test is specific for LA, because they are prone to interference by other causes of elevated clotting times. Several screening tests are available but the pairing of dilute Russell's viper venom time (dRVVT) with LA-sensitive activated partial thromboplastin time (aPTT) is widely used and recommended because it is proven to have good detection rates. Nonetheless, judicious use of other assays can improve diagnostic performance, such as dilute prothrombin time to find LA unreactive with dRVVT and aPTT, and the recently validated Taipan snake venom time with ecarin time confirmatory test that are unaffected by vitamin K antagonist and direct factor Xa inhibitor anticoagulation. Expert body guidelines and their updates have improved harmonization of laboratory practices, although some issues continue to attract debate, such as the place of mixing tests in the medley hierarchy, and areas of data manipulation such as assay cut-offs and ratio generation. This article reviews current practices and challenges in the laboratory detection of LA.
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Affiliation(s)
- Gary W Moore
- Haemostasis Unit, Department of Haematology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom.,Department of Natural Sciences, Faculty of Science and Technology, Middlesex University, London, United Kingdom
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Ling LQ, Liu CN, Huang XB, Liao J, Jia J, Zhou J. Interpretation of clot-based lupus anticoagulant assays-Normalizing clotting time against different denominators. Int J Lab Hematol 2022; 44:777-784. [PMID: 35297205 DOI: 10.1111/ijlh.13830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/24/2022] [Accepted: 03/02/2022] [Indexed: 02/05/2023]
Abstract
OBJECTIVES The endpoint for all lupus anticoagulant (LA) assays is a clotting time in seconds. This study aimed to clarify the use of normalizing clotting time to ratio and how the use of different denominators is relevant. METHODS Whether normalization could reduce reagent variability and possess better diagnostic performances was assessed; denominators included reference interval (RI) mean, local-obtained pooled plasma clotting time, standard plasma clotting time, and control plasma clotting time (CNPPct). Moreover, whether day-to-day variation in CNPPct would impact its application was studied. RESULTS If not normalized, significant difference existed among different reagent batches; if normalized (against any denominators), no statistically significant difference existed anymore. The validation of in-house RIs achieved a 100% success rate. Normalization against different denominators had different RIs, but the same diagnostic efficacies (when a prolonged LA1 is used to suggest further LA-related testings, normalized LA1 demonstrated a better sensitivity: 1.0 vs. 0.95). Normalization against a "daily" CNPPct (obtained alongside test plasmas day to day) demonstrated low inter-day variations (LA1: ~1%, LA2: ~1%), and it could employ the RI for normalization against a "fixed" CNPPct (obtained alongside normal plasmas when the RI was established). CONCLUSIONS Normalizing clotting time reduces reagent-batch variability and promotes the adoption of common RIs, and therefore reduces the necessity of establishing RI for new reagent batches. Normalized LA1 is more sensitive when used to suggest further LA-related testings, and therefore reduces the rate of missed LA diagnosis. All denominators are of the same application value. Day-to-day variation in CNPPct did not impact its application as a reliable denominator.
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Affiliation(s)
- Li-Qin Ling
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Chao-Nan Liu
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Xun-Bei Huang
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Juan Liao
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Jin Jia
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Jing Zhou
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, China
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11
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Moore GW. Mixing studies for lupus anticoagulant: mostly no, sometimes yes. Clin Chem Lab Med 2021; 58:492-495. [PMID: 31874095 DOI: 10.1515/cclm-2019-1248] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 12/04/2019] [Indexed: 12/12/2022]
Abstract
Mixing tests have long been a mainstay in the lupus anticoagulant (LA) testing armoury of screen, mix and confirm assays. If a sample with an elevated screening test does not evidence inhibition in the mixing test, the search for an LA is halted and a different diagnostic pathway embarked upon. Recent years have seen studies evidencing sometimes high frequencies of false-negative mixing tests with perhaps sinister implications for missed diagnoses and skewed patient management. Issues such as the dilution effect, between-reagent sensitivity and specificity differences, variability of normal pooled plasma (NPP) quality and suitability and interpretive inconsistencies all contribute to questioning the reliability of mixing tests and their pivotal place in the LA assay hierarchy. The advent of integrated testing, where phospholipid-dependence is demonstrated or excluded prior to any attempt to evidence inhibitory properties with a fallible analytical principle, provides an alternative path to LA detection. In the absence of other causes of elevated clotting times, LA assay screen and confirm discordance is sufficient to secure a laboratory diagnosis of the presence of an LA, leaving the mixing test in a supplementary yet valuable role when further diagnostic discrimination is required.
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Affiliation(s)
- Gary W Moore
- Department of Haematology, Specialist Haemostasis Unit, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
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12
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Kumano O, Amiral J, Dunois C, Peyrafitte M, Moore GW. Applying index of circulating anticoagulant to mixing tests with lupus anticoagulant screen and confirm reagents can distinguish with high specificity between lupus anticoagulants and direct factor Xa inhibitors. Int J Lab Hematol 2021; 43:771-778. [PMID: 33974363 DOI: 10.1111/ijlh.13571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 04/11/2021] [Accepted: 04/14/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Lupus anticoagulants (LA) are detected by prolongation of clotting times for dilute Russell's viper venom time (dRVVT) and activated partial thromboplastin time (APTT) screening tests. Direct oral anticoagulants (DOACs) can interfere with both screening and confirmatory tests. The present study aimed to investigate the influence of direct factor Xa inhibitors (DiXaIs) on screen, confirm and mixing tests and establish a method for differentiation from other sample types. MATERIALS AND METHODS A total of 257 samples including nonanticoagulated LA positive, LA positive with DiXaIs, factor deficiency, FVIII inhibitors, warfarin and non-APS DiXaIs were tested. APTT reagents Cephen LS/Cephen and dRVVT reagents LA1/LA2 were used, respectively, to screen/confirm the study group. Index of circulating anticoagulant (ICA) was calculated from clotting times based on the following formula as ICA screening and ICA confirmation. ICA= (1:1 Mix sample - Normal pooled plasma) / Screen patient x 100. An ICA matrix was established which suggested the presence of a DiXaI when both ICA screening and confirmation were above the cut-off. When only ICA screening is elevated, LA is suspected. RESULTS Sensitivity and specificity of the ICA matrix were 52.2% and 92.8% for DiXaIs and 38.1% and 96.7% for LA in APTT, and 61.2% and 92.9% for DiXaIs and 22.2% and 88.4% for LA in dRVVT, respectively. CONCLUSION The ICA matrix achieved high specificity with a lower apparent sensitivity for DiXaI samples comparatively to other devices but due only to less interferences: the matrix could contribute to differentiating DiXaIs from LA in samples where anticoagulation status is unknown.
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Affiliation(s)
- Osamu Kumano
- Protein Technology, Engineering 1, Sysmex Corporation, Kobe, Japan
| | - Jean Amiral
- Research Department, Hyphen BioMed, Neuville sur Oise, France
| | - Claire Dunois
- Research Department, Hyphen BioMed, Neuville sur Oise, France
| | | | - Gary W Moore
- Department of Haematology, Specialist Haemostasis Unit, Addenbrooke's Hospital, Cambridge, UK.,Faculty of Science and Technology, Middlesex University, London, UK.,Department of Haemostasis and Thrombosis, Viapath Analytics, St. Thomas' Hospital, London, UK
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Shimonishi N, Ogiwara K, Oda Y, Kawabe T, Emmi M, Shima M, Nogami K. Inhibitor Index in the Clot Waveform Analysis-Based Mixing Test Differentiates among Hemophilia A without and with Inhibitors, and Lupus Anticoagulant. Thromb Haemost 2021; 121:792-799. [PMID: 33412612 DOI: 10.1055/s-0040-1721776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
BACKGROUND The mixing test is used to identify the pathway to follow-up testing and is also useful for the investigation of lupus anticoagulant (LA) positivity. "To completely correct" indicates clotting factor deficiency, while "to not correct" indicates the presence of a clotting factor inhibitor including LA. "Index of circulation anticoagulant" and/or "percent correction" is used to interpret the results of mixing studies, but it does not accurately differentiate factor inhibitors from LA. AIM To precisely differentiate hemophilia A (HA), HA with inhibitor (HA-inh), and LA using the clot waveform analysis (CWA)-based mixing test. METHODS Plasma samples from HA, LA, and HA-inh including acquired HA were incubated with normal plasma in 9:1, 1:1, and 1:9 mix ratios. From activated partial thromboplastin time CWA at 0-minute (immediately) and 12-minute incubation, the ratios of CWA parameters at 12 minutes/0 minute (inhibitor index) were assessed. RESULTS The inhibitor index values of CWA parameters obtained using the mixing test in a 1:1 ratio demonstrated a significant difference between HA-inh and LA but could not differentiate LA from HA-inh completely. Plasmas used for the mixing tests in 9:1 and 1:9 ratios were able to fully distinguish between HA-inh (>0.5 BU/mL) and LA. These indices significantly correlated with inhibitor titer below 40 BU/mL (r > 0.90), possibly estimating FVIII inhibitor titer from the inhibitor index. Plasmas in HA and LA could be distinguished by mixing in a 1:1 ratio at 0 minute (immediately). CONCLUSION The inhibitor index from CWA-based mixing tests with a 12-minute incubation could differentiate among HA, HA-inh, and LA quickly.
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Affiliation(s)
- Naruto Shimonishi
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
| | - Kenichi Ogiwara
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
| | - Yukio Oda
- SEKISUI MEDICAL CO., LTD., Tokyo, Japan
| | | | - Mari Emmi
- SEKISUI MEDICAL CO., LTD., Tokyo, Japan
| | - Midori Shima
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
| | - Keiji Nogami
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
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Moore GW, Kumano O. Lupus anticoagulant assay cut-offs vary between reagents even when derived from a common set of normal donor plasmas. J Thromb Haemost 2020; 18:439-444. [PMID: 31663664 DOI: 10.1111/jth.14669] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/20/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND Multicenter studies reveal that diagnostic efficacy of lupus anticoagulant (LA) assays is enhanced if cut-offs are locally generated. However, a potential confounder is the inevitable use of separate normal donor populations. OBJECTIVES Generate cut-offs for multiple LA reagents with the same analyzer and normal donor plasmas. METHODS Cut-offs for screen ratio, confirm ratio, percent correction of screen ratio by confirm ratio, and normalized screen/confirm ratio (NSCR) were derived from the same 50 normal donor plasmas for screen and confirm pairs for two dilute Russell's viper venom time reagents, LA1/LA2 and HEMOCLOT™ LA-S/LA-C, and two APTTs, Actin FSL/FS and Cephen LS/Cephen. The cut-offs were challenged with plasmas from 20 triple-positive APS patients and 25 plasmas from LA-negative, thrombotic patients. RESULTS Cut-offs for screen ratio, confirm ratio, percent correction, and NSCR, respectively, were 1.12/1.08/8.3/1.09 for LA1/LA2; 1.17/1.10/13.6/1.13 for HEMOCLOT™ LA-S/LA-C; 1.12/1.13/9.7/1.10 for Actin FSL/FS; 1.09/1.13/11.0/1.11 for Cephen LS/Cephen. LA1 and LA-S screens were elevated in 19/20 and 16/20 triple-positive plasmas, respectively, while 20/20 were detected with both via integrated interpretation ie, percent correction or NSCR irrespective of screen elevation. Actin FSL and Cephen LS screens were elevated in 17/20 and 19/20 triple-positive plasmas, respectively, while one more LA was detected with Actin FSL via integrated interpretation, but not for Cephen LS. Integrated interpretation suggested 5/25 LA-negative plasmas contained weak LA (two with Actin FSL/FS, two with LA1/LA2, one with LA-S/LA-R). CONCLUSIONS Employing the same normal donor plasmas and analytical platform does not compensate for between-reagent differences when generating LA assay cut-offs.
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Affiliation(s)
- Gary W Moore
- Department of Haemostasis and Thrombosis, Viapath Analytics, Guy's & St. Thomas' Hospitals, London, UK
| | - Osamu Kumano
- Protein Technology, Sysmex Corporation, Kobe, Japan
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Favaloro EJ. Coagulation mixing studies: Utility, algorithmic strategies and limitations for lupus anticoagulant testing or follow up of abnormal coagulation tests. Am J Hematol 2020; 95:117-128. [PMID: 31674066 DOI: 10.1002/ajh.25669] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/24/2019] [Accepted: 10/28/2019] [Indexed: 01/08/2023]
Abstract
Coagulation testing underpins the investigation of hemostasis and/or monitoring of anticoagulation therapy for prevention and/or treatment of thrombosis related pathology. Assessment of coagulation results requires comparison against a normal reference range or interval (NRR/NRI). Results flagged as "abnormal" (ie, above the NRR/NRI for patients not on anticoagulant therapy), typically require further evaluation. eg, follow up or reflexive testing is used to identify the reason for prolongation, especially when supported by clinical context (eg, bleeding). Mixing tests may have utility to help identify the pathway of follow-up testing (ie, towards investigation of factor deficiencies, or else inhibitors), and are also useful for investigation of lupus anticoagulants (LA). In general, mixing tests that "correct" tend to suggest the presence of factor deficiencies, where as those that do not correct suggest the presence of "inhibitors". Various approaches can be used to identify correction/non-correction, and all have strengths and limitations. Furthermore, eventual identification of causal factor deficiencies or even "inhibitors" may (eg, factor VIII or IX deficiencies or inhibitors) or may not (eg, factor XII deficiency) be clinically important. Ultimately, mixing studies performed in view of appropriate clinical scenarios (eg, bleeding patient) and for LA investigations in symptomatic patients will have best utility.
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Affiliation(s)
- Emmanuel J. Favaloro
- Department of HaematologyInstitute of Clinical Pathology and Medical Research (ICPMR), Sydney Centres for Thrombosis and Haemostasis, NSW Health Pathology, Westmead Hospital Westmead New South Wales Australia
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Kumano O, Moore GW. Ruling out lupus anticoagulants with mixing test-specific cutoff assessment and the index of circulating anticoagulant. Res Pract Thromb Haemost 2019; 3:695-703. [PMID: 31624789 PMCID: PMC6781930 DOI: 10.1002/rth2.12245] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 06/18/2019] [Accepted: 06/27/2019] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Lupus anticoagulant (LA) is classified in the antibody family that is recognized in antiphospholipid syndrome. Mixing tests are recommended for LA detection, and either a mixing test-specific cutoff (MTC) or index of circulating anticoagulant (ICA) is used for the interpretation. Although we previously showed MTC had higher sensitivity for LA than ICA, there are few studies investigating specificity. OBJECTIVES To investigate specificity of multiple activated partial thromboplastin time (APTT) and diluted Russell's viper venom time (dRVVT) reagents for inhibitors using plasmas with non-LA causes of prolonged clotting times, interpreted with MTC and ICA. METHODS Seventy-six factor-deficient samples (either artificially prepared, hereditary deficiency, or warfarin), and 12 inhibitors (either coagulation factor inhibitors, rivaroxaban, or apixaban) were used. Samples were tested with 4 APTTs, 1 dilute APTT (dAPTT), and 2 dRVVT reagents, and all elevated screen ratios were followed up with mixing tests. Frequencies of corrected and not-corrected results were calculated. RESULTS The frequency of MTC and ICA corrected results, suggesting factor deficiency, were 5% to 43% and 79% to 100%, respectively, except for dAPTT, where MTC and ICA performed similarly. Frequencies of MTC and ICA not-corrected results, suggesting inhibition, were 29% to 100% and 25% to 67%, respectively. CONCLUSIONS The data indicate that MTC has a tendency to generate not-corrected mixing tests in factor-deficient, warfarin, and other inhibitor samples, while ICA exhibited higher specificity. When we perform the mixing test and interpret the data, it is important to understand the characteristics of the indexes for maximizing the diagnostic potential of mixing test.
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Affiliation(s)
- Osamu Kumano
- Protein TechnologySysmex CorporationKobeHyogoJapan
| | - Gary W. Moore
- Department of Haemostasis and ThrombosisViapath AnalyticsGuy's & St. Thomas’ HospitalsLondonUK
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Florin L, Desloovere M, Devreese KMJ. Evaluation of an automated algorithm for interpretation of lupus anticoagulant testing. Int J Lab Hematol 2019; 41:412-417. [DOI: 10.1111/ijlh.13001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 02/08/2019] [Accepted: 02/11/2019] [Indexed: 01/16/2023]
Affiliation(s)
- Lisa Florin
- Coagulation Laboratory, Department of Laboratory Medicine Ghent University Hospital Ghent Belgium
| | - Maxime Desloovere
- Coagulation Laboratory, Department of Laboratory Medicine Ghent University Hospital Ghent Belgium
| | - Katrien M. J. Devreese
- Coagulation Laboratory, Department of Laboratory Medicine Ghent University Hospital Ghent Belgium
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Kumano O, Amiral J, Dunois C, Peyrafitte M, Moore GW. Paired APTTs of low and high lupus anticoagulant sensitivity permit distinction from other abnormalities and achieve good lupus anticoagulant detection rates in conjunction with dRVVT. Int J Lab Hematol 2018; 41:60-68. [PMID: 30248243 DOI: 10.1111/ijlh.12921] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 07/22/2018] [Accepted: 07/31/2018] [Indexed: 01/03/2023]
Abstract
INTRODUCTION A prolonged activated partial thromboplastin time (APTT) may be indicative of a specific or multiple factor deficiency, therapeutic anticoagulation, presence of a nonspecific factor inhibitor, or lupus anticoagulant (LA). Recently, pairing of the LA-sensitive APTT and standard APTT reagents, Cephen LS and Cephen, respectively, has been shown to be effective in LA detection. The present study aimed to evaluate the usefulness of this reagent pair for discriminating between causes of APTT elevation and the detection of LA in conjunction with dilute Russell's viper venom time (dRVVT). METHODS Plasma samples from 50 normal and 105 non-anticoagulated LA-positive patients in routine dRVVT and/or dilute APTT (dAPTT) via the percent correction formula were employed. Cephen LS/Cephen and dRVVT reagents LA1/LA2 were used to screen/confirm, respectively. Thirty-four symptomatic LA-negative, 25 warfarinised non-antiphospholipid syndrome, 6 coagulation inhibitors, 17 samples with hereditary elevated APTT, and 24 FVIII/IX/XI/XII and 17 FII/V/X artificial single deficiency plasmas were used. RESULTS Thirty-three samples out of 105 (31%) were LA-positive in Cephen LS/Cephen. The total percent positivity in Cephen LS/Cephen and LA1/LA2 pairs was 89.1% against samples with the routine dRVVT/dAPTT double positive. The percent corrections of Cephen LS/Cephen in the routine dAPTT/dRVVT positive group were significantly higher than those in all other groups. CONCLUSIONS The percent correction of the APTT reagent pair showed higher values in LA-positive samples. The combination will be useful with respect to differentiating LA from other abnormal samples and is effective in LA detection when paired with dRVVT.
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Affiliation(s)
- Osamu Kumano
- Protein Technology, Sysmex Corporation, Kobe, Hyogo, Japan
| | | | | | | | - Gary W Moore
- Department of Haemostasis and Thrombosis, Viapath Analytics, Guy's & St Thomas' Hospitals, London, UK
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