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Bonnefoy A, Merlen C, Dubé E, Claus-Desbonnet H, Rivard GE, St-Louis J. Predictive significance of anti-FVIII immunoglobulin patterns on bleeding phenotype and outcomes in acquired hemophilia A: Results from the Quebec Reference Center for Inhibitors. J Thromb Haemost 2021; 19:2947-2956. [PMID: 34455699 DOI: 10.1111/jth.15515] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 08/23/2021] [Accepted: 08/26/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Acquired hemophilia A (AHA) is a potentially life-threatening bleeding disorder caused by factor VIII (FVIII) autoantibodies, involving various immunoglobulin (Ig) isotypes and IgG subclasses. OBJECTIVES We analyzed the profile of Ig against FVIII in patients with AHA to identify Ig patterns predictive of bleeding phenotype and outcomes. PATIENTS/METHODS Ig detection and titration were determined by enzyme-linked immunosorbent assay (ELISA) at disease presentation in a cohort of 66 subjects from the Quebec Reference Centre for Inhibitors registry. RESULTS Most of plasma samples analyzed (97%) contained multiple anti-FVIII Ig isotypes and IgG subclasses, IgG(1,2,3,4) (24.2%), [IgG(1,2,3,4),IgA] (16.7%) and IgG(2.4) (13.6%) being the most prevalent combinations of Ig detected. AHA patients who presented with IgA antibodies were more likely to have an associated auto-immune disease (p = .049). The presence of IgG4-was associated with bleeding symptoms at presentation (p = .002). IgG1-positive patients were more likely to require transfusions with red packed cell (p = .014) whereas IgM detection was associated with a higher probability of death linked to AHA (p = .011). CONCLUSION The Ig pattern of AHA patients at diagnosis is widely heterogeneous and is at least partially associated with some underlying conditions. Our data supports the differential predictive significance for IgG1, IgG4 and IgM on bleeding severity and suggests that the early determination of Ig profile may help to identify AHA patients at higher risk of poorer outcomes.
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Affiliation(s)
- Arnaud Bonnefoy
- Division of Hematology-Oncology, Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada
| | - Clémence Merlen
- Division of Hematology-Oncology, Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada
| | - Evemie Dubé
- Division of Hematology-Oncology, Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada
| | - Hadrien Claus-Desbonnet
- Division of Hematology-Oncology, Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada
| | - Georges-Etienne Rivard
- Division of Hematology-Oncology, Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada
| | - Jean St-Louis
- Division of Hematology-Oncology, Hôpital Maisonneuve-Rosemont, Montreal, Quebec, Canada
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Delianu C, Moscalu M, Hurjui LL, Tărniceriu CC, Bădulescu OV, Lozneanu L, Hurjui I, Goriuc A, Surlari Z, Foia L. Chronometric vs. Structural Hypercoagulability. ACTA ACUST UNITED AC 2020; 57:medicina57010013. [PMID: 33379139 PMCID: PMC7823593 DOI: 10.3390/medicina57010013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/15/2020] [Accepted: 12/21/2020] [Indexed: 11/16/2022]
Abstract
Prolonged tourniquet stasis induced by venepuncture can lead to the release of the plasma of cell lysis products, as well as tissue factor (TF), impairing the quality of coagulation test results. The accidental presence of TF in vitro can trigger the coagulation mechanism, generating a false decrease in prothrombin time (PT). Background and Objectives: Identification of short PT tests below the normal reference value that could suggest a situation of hypercoagulability. The study aimed to compare the results of the shortened PT tests at their first determination with the eventual correction following duplication of the analysis from the same sample. Materials and methods: Identification of the shortened PT tests has been carried out for a period of 4 months, upon 544 coagulation samples referred to the Hematology department of Sf. Spiridon County Clinical Emergency Hospital from Iasi, Romania. Results: Out of the 544 samples of which the results indicated a state of hypercoagulability, by repeating the determination from the same sample, for 200 (36.76%) PT tests (p = 0.001) the value was corrected, falling within the normal reference range. For 344 (63.24%) tests, the results suggested a situation of hypercoagulability. Conclusions: In order to guarantee the highest quality of the laboratory services, a proper interpretation and report of the patients' results must be congruent and harmoniously associated to the actual clinical condition of the patient. Duplication of the PT determination from the same sample would exclude situations of false hypercoagulability and would provide significant improvement for the patient's safety.
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Affiliation(s)
- Carmen Delianu
- Department of Biochemistry, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (C.D.); (A.G.); (L.F.)
- Central Clinical Laboratory—Hematology Department, “Sf. Spiridon” County Clinical Emergency Hospital, 700111 Iasi, Romania
| | - Mihaela Moscalu
- Department of Preventive Medicine and Interdisciplinarity, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania
- Correspondence: (M.M.); (L.L.H.)
| | - Loredana Liliana Hurjui
- Central Clinical Laboratory—Hematology Department, “Sf. Spiridon” County Clinical Emergency Hospital, 700111 Iasi, Romania
- Department of Morpho-Functional Sciences II, Discipline of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
- Correspondence: (M.M.); (L.L.H.)
| | - Claudia Cristina Tărniceriu
- Department of Morpho-Functional Sciences I, Discipline of Anatomy, “Grigore T. Popa” University of Medicine and Pharmacy, Universității str. 16, 700115 Iasi, Romania;
- Hematology Clinic, “Sf. Spiridon” County Clinical Emergency Hospital, 700111 Iasi, Romania
| | - Oana-Viola Bădulescu
- Department of Morpho-Functional Sciences II, Discipline of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
- Hematology Clinic, “Sf. Spiridon” County Clinical Emergency Hospital, 700111 Iasi, Romania
| | - Ludmila Lozneanu
- Department of Morpho-Functional Sciences I, Discipline of Histology, “Grigore T. Popa” University of Medicine and Pharmacy, Universității str. 16, 700115 Iasi, Romania;
- Department of Pathology, “Sf. Spiridon” Emergency County Hospital, 700111 Iasi, Romania
| | - Ion Hurjui
- Department of Morpho-Functional Sciences II, Discipline of Biophysics, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
| | - Ancuta Goriuc
- Department of Biochemistry, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (C.D.); (A.G.); (L.F.)
| | - Zinovia Surlari
- Department of Odontology and Parodontology, “Grigore T. Popa” University of Medicine and Pharmacy, Universității str. 16, 700115 Iasi, Romania;
| | - Liliana Foia
- Department of Biochemistry, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (C.D.); (A.G.); (L.F.)
- Central Clinical Laboratory—Biochemistry Department, “Sf. Spiridon” County Clinical Emergency Hospital, 700111 Iasi, Romania
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3
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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: 24] [Impact Index Per Article: 6.0] [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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4
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Batty P, Moore G, Platton S, Maloney J, Palmer B, Bowles L, Pasi J, Rangarajan S, Hart D. Diagnostic accuracy study of a factor VIII ELISA for detection of factor VIII antibodies in congenital and acquired haemophilia A. Thromb Haemost 2017; 114:804-11. [DOI: 10.1160/th14-12-1062] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 05/19/2015] [Indexed: 11/05/2022]
Abstract
SummaryAntibody formation to factor VIII (FVIII) remains the greatest clinical and diagnostic challenge to the haemophilia-treating physician. Current guidance for testing for inhibitory FVIII antibodies (inhibitors) recommends the functional Nijmegen-Bethesda assay (NBA). A FVIII ELISA offers a complementary, immunological approach for FVIII antibody testing. It was the aim of this study to retrospectively evaluate the performance of a FVIII ELISA (index) for detection of FVIII antibodies, compared with the NBA (reference). All samples sent for routine FVIII antibody testing at two haemophilia Comprehensive Care Centres, were tested in parallel using the NBA and a solid-phase, indirect FVIII ELISA kit (Immucor). A total of 497 samples from 239 patients (severe haemophilia A=140, non-severe haemophilia A=85, acquired haemophilia A=14) were available for analysis. Sixty-THree samples tested positive by the NBA (prevalence 12.7 %, 95 % confidence interval [CI], 9.9–15.9 %), with a median inhibitor titre of 1.2 BU/ml (range 0.7–978.0). The FVIII ELISA demonstrated a specificity of 94.0 % (95 %CI, 91.3–96.0), sensitivity of 77.8 % (95 %CI, 65.5–87.3), negative predictive value of 96.7 % (95 %CI, 94.5–98.2), positive predictive value 65.3 % (95 %CI, 53.5–76.0), negative likelihood ratio 0.2 (95 %CI, 0.1–0.4), positive likelihood ratio 13.0 (95 %CI, 8.7–19.3) and a diagnostic odds ratio of 54.9 (95 %CI, 27.0–112.0). Strong positive correlation (r=0.77, p< 0.001) was seen between the results of the NBA (log adjusted) and FVIII ELISA optical density. In conclusion, FVIII ELISA offers a simple, specific, surveillance method enabling batch testing of non-urgent samples for the presence of FVIII antibodies.
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Tripodi A, Chantarangkul V, Cini M, Devreese K, Dlott JS, Giacomello R, Gray E, Legnani C, Martinuzzo ME, Pradella P, Siegemund A, Subramanian S, Suchon P, Testa S. Variability of cut-off values for the detection of lupus anticoagulants: results of an international multicenter multiplatform study. J Thromb Haemost 2017; 15:1180-1190. [PMID: 28316135 DOI: 10.1111/jth.13678] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Indexed: 11/29/2022]
Abstract
Essentials Between-lab variations of cut-off values in lupus anticoagulant detection are unknown. Cut-off values were calculated in 11 labs each testing plasma from 120 donors with 3 platforms. Major variation was observed even within the same platform. Cut-off values determined in different labs are not interchangeable. SUMMARY Background Cut-off values for interpretation of lupus anticoagulant (LA) detection are poorly investigated. Aims (i) To assess whether results from healthy donors were normally distributed and (ii) the between-laboratories differences in cut-off values for screening, mixing and LA confirmation when calculated as 99th or 95th centiles, and (iii) to assess their impact on the detection rate for LA. Methods Each of 11 laboratories using one of the three widely used commercial platforms for LA detection was asked to collect plasmas from 120 healthy donors and to perform screening, mixing and LA confirmation with two methods (activated partial thromboplastin time [APTT] and dilute Russell viper venom [dRVV]). A common set of LA-positive or LA-negative freeze-dried plasmas was used to assess the LA detection rate. Results were centralized (Milano) for statistical analysis. Results and conclusions (i) Clotting times or ratios for healthy subjects were not normally distributed in the majority of cases. The take-home message is that cut-off values should be determined preferably by the non-parametric method based on centiles. (ii) There were relatively large inter-laboratory cut-off variations even within the same platform and the variability was marginally attenuated when results were expressed as ratios (test-to-normal pooled plasma). The take-home message is that cut-off values should be determined locally. (iii) There were differences between cut-off values calculated as 99th or 95th centiles that translate into a different LA detection rate (the lower the centile the greater the detection rate). The take-home message is that cut-off values determined as the 95th centile allow a better LA detection rate.
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Affiliation(s)
- A Tripodi
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Department of Clinical Sciences and Community Health, Università degli Studi di Milano and IRCCS Maggiore Hospital Foundation, Milano, Italy
| | - V Chantarangkul
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Department of Clinical Sciences and Community Health, Università degli Studi di Milano and IRCCS Maggiore Hospital Foundation, Milano, Italy
| | - M Cini
- Department of Angiology and Blood Coagulation, University Hospital Sant'Orsola-Malpighi, Bologna, Italy
| | - K Devreese
- Coagulation Laboratory, Department of Laboratory Medicine, Ghent-University Hospital, Ghent, Belgium
| | - J S Dlott
- Quest Diagnostics, Chantilly, VA, USA
| | - R Giacomello
- Department of Medical and Biological Sciences, University of Udine, Udine, Italy
- Department of Laboratory Medicine, ASUI UD, University Hospital, Udine, Italy
| | - E Gray
- National Institute for Biological Standards and Controls, Potters Bar, UK
| | - C Legnani
- Department of Angiology and Blood Coagulation, University Hospital Sant'Orsola-Malpighi, Bologna, Italy
| | - M E Martinuzzo
- Laboratorio Central del Hospital Italiano de Buenos Aires, Instituto Universitario del Hospital Italiano, Buenos Aires, Argentina
| | - P Pradella
- Haemostasis Laboratory, Department of Transfusion Medicine, ASUI TS, University Hospital of Cattinara, Trieste, Italy
| | | | - S Subramanian
- Department of Clinical Pathology, St John's Medical College Hospital, Bangalore, India
| | - P Suchon
- Assistance Publique des Hopitaux de Marseille, Marseille, France
- Institut National pour la Santé et la Recherche Médicale (INSERM), Unité Mixte de Recherche en Santé (UMR_S) 1062, Nutrition Obesity and Risk of Thrombosis, Aix-Marseille University, Marseille, France
| | - S Testa
- Haemostasis and Thrombosis Center, General Hospital, Cremona, Italy
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Adcock DM, Favaloro EJ, Lippi G. Critical pre-examination variables in the hemostasis laboratory and their quality indicators. Clin Biochem 2016; 49:1315-1320. [DOI: 10.1016/j.clinbiochem.2016.08.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 08/30/2016] [Accepted: 08/31/2016] [Indexed: 10/21/2022]
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7
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Doma SA, Hillarp A, Pajič T, Andoljšek D, Černelč P, Preldžnik Zupan I. Concurrent acquired inhibitors to factor VIII and IX, a laboratory artifact: a case report. Biochem Med (Zagreb) 2016; 26:279-84. [PMID: 27346976 PMCID: PMC4910271 DOI: 10.11613/bm.2016.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 05/21/2016] [Indexed: 11/23/2022] Open
Abstract
Acquired inhibitors to coagulation factors other than factor VIII are extremely rare. We describe a case of a 59-year-old woman with abnormal bleeding, diagnosed with concurrent inhibitor antibodies to factor VIII and IX by Bethesda testing. We demonstrate that anti-FVIII antibodies of a very high titre are capable of disturbing the aPTT-based Bethesda assay, resulting in falsely-positive antibodies to factor IX. The case also illustrates the usefulness of the immunological assay (ELISA) in complementing the inhibitor diagnosis.
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Affiliation(s)
- Saša Anžej Doma
- Department of Hematology, University Medical Centre Ljubljana, Slovenia
| | - Andreas Hillarp
- Department of Clinical Chemistry and Transfusion Medicine, Halland Hospital, Halmstad, Sweden ; at the time of the investigation working at the Coagulation laboratory of Malmö Centre for Thrombosis and Haemostasis, Skane University Hospital, Malmö, Sweden
| | - Tadej Pajič
- Department of Hematology, University Medical Centre Ljubljana, Slovenia
| | - Dušan Andoljšek
- Department of Hematology, University Medical Centre Ljubljana, Slovenia
| | - Peter Černelč
- Department of Hematology, University Medical Centre Ljubljana, Slovenia
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8
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Adcock DM, Favaloro EJ. Pearls and pitfalls in factor inhibitor assays. Int J Lab Hematol 2016; 37 Suppl 1:52-60. [PMID: 25976961 DOI: 10.1111/ijlh.12352] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 03/10/2015] [Indexed: 12/30/2022]
Abstract
The proper performance and interpretation of factor inhibitor assays is a critical role for the hemostasis laboratory. Both false-positive and false-negative inhibitor assays may be reported, leading to serious patient mismanagement. Knowledge and recognition of common causes of both false-positive and negative-results can aid in the identification of these potential pitfalls. Safeguards to reporting accurate factor inhibitor assays include initial characterization of the sample, using the Nijmegen modification, properly performing and interpreting an incubated mixing test in conjunction, and performing two dilutions for each dependent dilution in the factor inhibitor assay.
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Affiliation(s)
- D M Adcock
- Colorado Coagulation, Laboratory Corporation of America® Holdings, Englewood, CO, USA
| | - E J Favaloro
- Department of Haematology, Institute of Clinical Pathology and Medical Research, Pathology West, NSW Health Pathology, Westmead Hospital, Sydney, NSW, Australia
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Lima-Oliveira G, Salvagno GL, Danese E, Favaloro EJ, Guidi GC, Lippi G. Sodium citrate blood contamination by K2-ethylenediaminetetraacetic acid (EDTA): impact on routine coagulation testing. Int J Lab Hematol 2014; 37:403-9. [DOI: 10.1111/ijlh.12301] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 09/15/2014] [Indexed: 01/12/2023]
Affiliation(s)
- G. Lima-Oliveira
- Laboratory of Clinical Biochemistry; Department of Life and Reproduction Sciences; University of Verona; Verona Italy
- Post-Graduate Program of Pharmaceutical Sciences; Department of Clinical Analyses; Federal University of Parana; Curitiba Parana Brazil
| | - G. L. Salvagno
- Laboratory of Clinical Biochemistry; Department of Life and Reproduction Sciences; University of Verona; Verona Italy
| | - E. Danese
- Laboratory of Clinical Biochemistry; Department of Life and Reproduction Sciences; University of Verona; Verona Italy
| | - E. J. Favaloro
- Department of Haematology; Institute of Clinical Pathology and Medical Research (ICPMR); Pathology West; Westmead Hospital; Westmead NSW Australia
| | - G. C. Guidi
- Laboratory of Clinical Biochemistry; Department of Life and Reproduction Sciences; University of Verona; Verona Italy
- Post-Graduate Program of Pharmaceutical Sciences; Department of Clinical Analyses; Federal University of Parana; Curitiba Parana Brazil
| | - G. Lippi
- Laboratory of Clinical Chemistry and Hematology; Academic Hospital of Parma; Parma Italy
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10
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Chang HH, Chiang BL. The diagnosis and classification of autoimmune coagulopathy: An updated review. Autoimmun Rev 2014; 13:587-90. [DOI: 10.1016/j.autrev.2014.01.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/13/2013] [Indexed: 10/25/2022]
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11
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W Collins P, Chalmers E, Hart D, Jennings I, Liesner R, Rangarajan S, Talks K, Williams M, R M Hay C. Diagnosis and management of acquired coagulation inhibitors: a guideline from UKHCDO. Br J Haematol 2013; 162:758-73. [PMID: 23889317 DOI: 10.1111/bjh.12463] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Peter W Collins
- School of Medicine, Cardiff University, University Hospital of Wales, Cardiff, UK
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Moser KA, Adcock Funk DM. Pitfalls in special coagulation testing: three illustrative case studies. Int J Lab Hematol 2013; 35:334-8. [PMID: 23480842 DOI: 10.1111/ijlh.12067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 01/09/2013] [Indexed: 11/27/2022]
Abstract
Assays in the special coagulation laboratory are affected by numerous factors, including pre-analytical variables, anticoagulant drugs, and abnormalities of the coagulation system other than the analyte specifically being examined. By reviewing special coagulation tests as a group and in concert with clinical information, as well as understanding assay methodologies, interferences can be more easily recognized and incorrect interpretations avoided, preventing possibly unnecessary treatment of patients. Three case studies involving protein S activity, von Willebrand factor analysis, and factor V activity with Bethesda titer will highlight potential pitfalls in the interpretation of special coagulation tests.
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Affiliation(s)
- K A Moser
- Colorado Coagulation/Esoterix Inc., 8490 Upland Drive, Englewood, CO 80112, USA.
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Abstract
Hemophilia A is an inherited bleeding disorder caused by a deficiency of factor VIII coagulant activity (FVIII:C). Patients are treated with infusions of either plasma-derived or recombinant factor VIII. However, some patients develop inhibitory antibodies (inhibitors) to infused factor VIII which render it ineffective. The original Bethesda method was developed to standardize measurement of inhibitors in a factor VIII neutralization assay. One Bethesda unit is defined as that amount of inhibitor that results in 50% residual FVIII:C activity of a defined test mixture. In the Nijmegen modification of the original Bethesda method, the pH and the protein concentration of the test mixture is further standardized. As a result, the FVIII:C in the test mixture is less prone to artifactual deterioration and the test has improved specificity. Even with a standardized procedure a number of factors can affect the performance of the test and it is important for laboratory staff to be aware of their impact on the result outcome.
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14
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Laboratory identification of factor inhibitors: an update. Pathology 2012; 44:293-302. [PMID: 22531341 DOI: 10.1097/pat.0b013e328353254d] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 01/19/2012] [Accepted: 01/29/2012] [Indexed: 11/26/2022]
Abstract
Coagulation factor inhibitors comprise antibodies that bind to and then neutralise specific pro-coagulant plasma proteins. Coagulation factor inhibitors can develop against any coagulation factor, although the most common are against factor VIII (FVIII). These can develop in individuals with inherited haemophilia A (HA) as an immune response to factor replacement therapy, or as auto-antibodies leading to the condition of acquired HA. Clinical suspicion for inhibitors may arise when individuals present with bleeding symptoms without any prior bleeding diathesis, or when a patient with known mild haemophilia presents with a bleeding diathesis more extreme to their usual presentation, or when there is failure of factor replacement therapy to arrest bleeding in a known haemophiliac. The laboratory identification of factor inhibitors requires a careful and systematic approach that excludes other possible causes of prolonged screening tests, most commonly the activated partial thromboplastin time (APTT), and sometimes prothrombin time (PT). Coagulation factor inhibitor studies, including the Bethesda assay, are then undertaken to measure inhibitor titre, which guides treatment. This paper overviews the laboratory investigation of factor inhibitors, and also briefly reviews recent cross-laboratory inhibitor studies and the most recent evidence related to differential inhibitor formation according to type of therapy.
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Favaloro EJ, (Adcock) Funk DM, Lippi G. Pre-analytical Variables in Coagulation Testing Associated With Diagnostic Errors in Hemostasis. Lab Med 2012. [DOI: 10.1309/lm749bqetkypypvm] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
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Abstract
The occurrence of an inhibitor against coagulation factor V (FV) is a rare but challenging condition, which may span from asymptomatic laboratory abnormalities to potentially life-threatening bleeding. The onset of FV inhibitors has been associated most frequently in the past with the patients' exposure to topical bovine thrombin administered during surgery procedures. However, since this preparation is no longer used, in this systematic review we have only focused on non-bovine thrombin-related FV inhibitor cases.
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Affiliation(s)
- Massimo Franchini
- Servizio di Immunoematologia e Medicina Trasfusionale, Dipartimento di Patologia e Medicina di Laboratorio, Azienda Ospedaliero-Universitaria di Parma, Parma, Italy.
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18
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Favaloro EJ, Wong RCW. Laboratory testing for the antiphospholipid syndrome: making sense of antiphospholipid antibody assays. Clin Chem Lab Med 2011; 49:447-61. [PMID: 21275808 DOI: 10.1515/cclm.2011.064] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The antiphospholipid syndrome (APS) is an autoimmune condition characterised by a wide range of clinical features (primarily thrombosis and/or obstetric related), associated with the presence of antiphospholipid antibodies (aPL) as detected by a diverse range of laboratory tests. APS remains a significant diagnostic challenge for clinicians across a wide range of specialities, largely due to issues related to laboratory testing as well as the expanding range of reported clinical manifestations of APS. The laboratory issues include limitations in detailed knowledge by both clinical and laboratory personnel regarding the 'complete' range of available aPL tests, as well as ongoing problems with assay reproducibility and standardisation. aPL are identified using diverse laboratory procedures based on one of two distinct test processes, namely solid phase and liquid phase assays. The former includes anticardiolipin antibodies (aCL) and anti-β(2)-glycoprotein I antibodies (aβ(2)GPI). The latter are centred on clot-based tests that are used to identify the so-called lupus anticoagulant (LA). This article will discuss: (i) issues related to laboratory testing for APS in terms of the currently available solid-phase and liquid-phase assays, and identifiable biases resulting from these tests usually being performed in different laboratories; (ii) current problems with calibration, standardisation and reproducibility of these assays; (iii) pre-analytical, analytical and post-analytical considerations and ongoing initiatives for improvement; (iv) issues related to potential combinations/panels of available aPL tests; and (v) the entities of seropositive APS, seronegative APS and non-APS aPL-positivity. In doing so, this review will hopefully help bridge the two disciplines of haematology and immunology ('representing' liquid-phase and solid-phase aPL testing, respectively), by improving the understanding of those working in each of these disciplines of the merits and limitations of the assays performed in the other discipline, and encouraging inter-discipline cooperation in the reporting of aPL test results.
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Affiliation(s)
- Emmanuel J Favaloro
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), Westmead Hospital, NSW, Australia.
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Dembitzer FR, Ledford Kraemer MR, Meijer P, Peerschke EI. Lupus anticoagulant testing: performance and practices by north american clinical laboratories. Am J Clin Pathol 2010; 134:764-73. [PMID: 20959659 DOI: 10.1309/ajcp4spplg5xvixf] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Lupus anticoagulant (LAC) testing is important for evaluating patients with antiphospholipid syndromes and hypercoagulable states. We reviewed results of proficiency testing challenges (n = 5) distributed by the North American Specialized Coagulation Laboratory Association to examine LAC testing performed by participating laboratories. The activated partial thromboplastin time (APTT) and dilute Russell viper venom time (dRVVT) constituted major testing methods. In screening studies, LAC-sensitive APTT methods were more sensitive to weak LAC than dRVVT-based methods but less specific. In confirmatory testing, dRVVT methods performed better, but performance was LAC-dependent. The highest false-negative confirmatory test results were obtained for the platelet neutralization procedure. Noncompliance with recommendations for LAC testing by the International Society on Thrombosis and Haemostasis was high (8%-38%), with the majority of noncompliant laboratories failing to report results of mixing studies. These data provide new insights into LAC testing in North America and identify opportunities for standardization.
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Favaloro EJ, Lippi G. Laboratory reporting of hemostasis assays: the final post-analytical opportunity to reduce errors of clinical diagnosis in hemostasis? Clin Chem Lab Med 2010; 48:309-21. [PMID: 20014957 DOI: 10.1515/cclm.2010.061] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The advent of modern instrumentation, with associated improvements in test performance and reliability, together with appropriate internal quality control (IQC) and external quality assurance (EQA) measures, has led to substantial reductions in analytical errors within hemostasis laboratories. Unfortunately, the reporting of incorrect or inappropriate test results still occurs, perhaps even as frequently as in the past. Many of these cases arise due to a variety of events largely outside the control of the laboratories performing the tests. These events are primarily preanalytical, related to sample collection and processing, but can also include post-analytical events related to the reporting and interpretation of test results. The current report provides an overview of these events, as well as guidance for prevention or minimization. In particular, we propose several strategies for the post-analytical reporting of hemostasis assays, and how this may provide the final opportunity to prevent serious clinical errors in diagnosis. This report should be of interest to both the laboratory scientists working in hemostasis and clinicians that request and attempt to interpret the test results. Laboratory scientists are ultimately responsible for these test results, and there is a duty to provide both accurate and precise results to enable clinicians to manage patients appropriately and to avoid the need to recollect and retest. Also, clinicians will not be in a position to best diagnose and manage their patient unless they gain an appreciation of these issues.
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Affiliation(s)
- Emmanuel J Favaloro
- Department of Hematology, Institute of Clinical Pathology and Medical Research ICPMR, Westmead Hospital, SWAHS, Westmead, NSW, Australia.
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LIPPI G, SALVAGNO GL, ADCOCK DM, GELATI M, GUIDI GC, FAVALORO EJ. Right or wrong sample received for coagulation testing? Tentative algorithms for detection of an incorrect type of sample. Int J Lab Hematol 2010; 32:132-8. [DOI: 10.1111/j.1751-553x.2009.01142.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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FAVALORO EJ, BONAR R, KERSHAW G, MOHAMMED S, DUNCAN E, MARSDEN K. Laboratory identification of factor VIII inhibitors in the real world: the experience from Australasia. Haemophilia 2010; 16:662-70. [DOI: 10.1111/j.1365-2516.2009.02173.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Pötzsch B, Oldenburg J. Inhibitordiagnostik. Hamostaseologie 2010. [DOI: 10.1007/978-3-642-01544-1_64] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Abstract
The presence of lupus anticoagulants (LA) in plasma alone or in combination with solid-phase antiphospholipid antibodies is an important prerequisite to define the antiphospholipid syndrome. The lack of specific tests to identify LA prompted standardization authorities to define a set of diagnostic criteria based on indirect evidence of the presence of LA and defined as screening, mixing and confirmatory studies. Accordingly, these studies must be carried out on patient plasmas and the relevant criteria satisfied before a firm diagnosis of LA can be made. Clinicians involved in LA testing should be aware of the limits which are inherent to this diagnosis, especially in patients who at the time of testing are on heparin and/or oral anticoagulant treatment, or are close to the acute thrombotic event. This article is aimed at reviewing the current situation and the light and shadows associated with this diagnostic procedure.
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Affiliation(s)
- A Tripodi
- Department of Internal Medicine, University Medical School, Mangiagalli and Regina Elena Foundation, Milano, Italy
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Peerschke EI, Castellone DD, Ledford-Kraemer M, Van Cott EM, Meijer P. Laboratory assessment of factor VIII inhibitor titer: the North American Specialized Coagulation Laboratory Association experience. Am J Clin Pathol 2009; 131:552-8. [PMID: 19289591 DOI: 10.1309/ajcpmkp94codilws] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Quantification of inhibitory antibodies against infused factor VIII (FVIII) has an important role in the management of patients with hemophilia A. This article summarizes results from the largest North American FVIII inhibitor proficiency testing challenge conducted to date. Test samples, 4 negative and 4 positive (1-3 Bethesda units [BU]/mL), were distributed by the ECAT Foundation in conjunction with the North American Specialized Coagulation Laboratory Association and analyzed by 38 to 42 laboratories in 2006 and 2007. Whereas laboratories were able to distinguish between the absence and presence of low-titer FVIII inhibitors, the intralaboratory coefficient of variation was high (30%-42%) for inhibitor-positive samples, and the definition of lower detection limits of the assay was variable (0-1 BU/mL). Most laboratories performed the Bethesda assay with commercially supplied buffered normal pooled plasma in a 1:1 mix with patient plasma. These data provide information for the development of consensus guidelines to improve FVIII inhibitor quantification.
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Favaloro EJ, Bonar R, Duncan E, Earl G, Low J, Aboud M, Just S, Sioufi J, Street A, Marsden K. Mis-identification of factor inhibitors by diagnostic haemostasis laboratories: recognition of pitfalls and elucidation of strategies. A follow up to a large multicentre evaluation. Pathology 2007; 39:504-11. [PMID: 17886101 DOI: 10.1080/00313020701569998] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
AIMS We previously reported the ability of diagnostic haemostasis facilities to identify coagulation factor abnormalities and inhibitors, through a large multi-centre study conducted on behalf of the Royal College of Pathologists of Australasia (RCPA) Quality Assurance Program (QAP). In the current report, additional data evaluation aims to (1) help identify the reasons behind the failures in inhibitor identification, (2) highlight the pitfalls in inhibitor testing, and (3) help elucidate some strategies for overcoming these problems and to assist in better identification and characterisation of inhibitors. METHODS Forty-two laboratories blind tested a set of eight samples for the presence or absence of inhibitors. These included true factor inhibitors (FVIII and FV), and other samples that reflected potential pre-analytical variables (e.g., heparin contamination, serum, EDTA plasma, aged plasma) that might arise and complicate inhibitor detection or lead to false inhibitor identification. RESULTS There was a wide scatter of inhibitor results, with false positive and false negative inhibitor identification, and mis-identification of inhibitors (e.g., FVIII inhibitor identified where FV inhibitor present). Further analysis of the pattern of reported laboratory results, including routine coagulation testing and factor profiles, allowed some additional interpretative power to provide strategies that will assist laboratories to improve the accuracy of inhibitor identification in the future. CONCLUSIONS There are currently occasional lapses in factor inhibitor identification, which this report will hopefully help address.
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Affiliation(s)
- Emmanuel J Favaloro
- Department of Haematology and Royal College of Pathologists of Australasia Quality Assurance Program, Institute of Clinical Pathology and Medical Research, Westmead Hospital, New South Wales 2145, Australia.
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Abstract
BACKGROUND Lupus anticoagulants (LA) are a heterogeneous class of immunoglobulins. Persistent LA positivity is a risk factor for the occurrence and recurrence of venous/arterial thromboembolism and/or pregnancy morbidity and qualifies the patient for anticoagulation therapy. The laboratory diagnosis for LA that is used for crucial decision-making about the optimal duration of the therapy rests entirely on diagnostic criteria. These criteria are based on the prolongation of phospholipid-dependent tests not corrected upon mixing patient and normal plasmas, with confirmation provided by the evidence that the anticoagulant is directed against proteins bound to negatively charged phospholipids. AIMS This article reviews issues related to the diagnosis of LA, including the effect of preanalytical variables, choice of tests, results interpretation of screening, mixing and confirmation procedures, patients to be investigated, and transmission of results. Unresolved issues and future direction for research on laboratory diagnosis are also discussed. METHODS Search of PubMed with the key term "lupus anticoagulant" plus articles and unpublished data known to the author. RESULTS AND CONCLUSIONS The preanalytical variables (i.e., plasma preparation and storage before analysis) as well as the diagnostic steps to detect LA present potential problems that undermine the process of making a correct diagnosis. A truly specific test for LA detection is badly needed, but its development may require understanding of the mechanisms associated with the occurrence of clinical events. Until then, clinical laboratories should rely on the existing procedures, which must be applied with caution and awareness of the many issues that may affect their results.
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Affiliation(s)
- Armando Tripodi
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Department of Internal Medicine, University of Milan and IRCCS Maggiore Hospital, Mangiagalli and Regina Elena Foundation, Milano, Italy.
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