Jean-Christophe Gris1, Éva Cochery-Nouvellon2, Chloé Bourguignon2, Éric Mercier3, Sylvie Bouvier2, Isabelle Quéré4, Antonia Perez-Martin5, Nicolas Molinari6, Éric Matzner-Lober7. 1. Department of Haematology, CHU Nîmes, Univ Montpellier, Nîmes, France; Faculty of Pharmaceutical and Biological Sciences, Montpellier University, France; UMR UA11 INSERM Institut Desbrest d'Epidémiologie et de Santé Publique, Montpellier University, France; I.M. Sechenov First Moscow State Medical University, Moscow, Russian Federation. Electronic address: jean.christophe.gris@chu-nimes.fr. 2. Department of Haematology, CHU Nîmes, Univ Montpellier, Nîmes, France; UMR UA11 INSERM Institut Desbrest d'Epidémiologie et de Santé Publique, Montpellier University, France. 3. Department of Haematology, CHU Nîmes, Univ Montpellier, Nîmes, France; Faculty of Pharmaceutical and Biological Sciences, Montpellier University, France; UMR UA11 INSERM Institut Desbrest d'Epidémiologie et de Santé Publique, Montpellier University, France. 4. UMR UA11 INSERM Institut Desbrest d'Epidémiologie et de Santé Publique, Montpellier University, France; Department of Vascular Medicine, University Hospital, Montpellier, France. 5. UMR UA11 INSERM Institut Desbrest d'Epidémiologie et de Santé Publique, Montpellier University, France; Department of Vascular Medicine, CHU Nîmes, Univ Montpellier, Nîmes, France. 6. Faculty of Pharmaceutical and Biological Sciences, Montpellier University, France; UMR UA11 INSERM Institut Desbrest d'Epidémiologie et de Santé Publique, Montpellier University, France. 7. UMR UA11 INSERM Institut Desbrest d'Epidémiologie et de Santé Publique, Montpellier University, France; CREST UMR 9194, ENSAE Formation Continue, 91120 Palaiseau, France.
Abstract
INTRODUCTION: No reference values are currently available for coagulation assays performed for thrombophilia screening prescribed according to guidelines, after a first venous thromboembolic (VTE) event, and we have no idea of the intra-patient associations between results. METHODS: We performed a retrospective study of consecutive prescriptions fulfilling guidelines in a French university hospital from 2010 to 2019 (n = 3842) from the Glims® laboratory information system. We collected results of 12 parameters: aPTT, PT, fibrinogen (Fg), one-stage clotting methods for factors VIII, IX, XI and II (FVIII, FIX, FXI, FII), antithrombin (using an amidolytic assay: AT), protein C and S (using clotting assays: PC and PS) and mixing tests of a lupus-anticoagulant sensitive aPTT and of DRVVT. RESULTS: We show the results of the 12 parameters from 3603 individual files with less than 6 missing values, then describe these distributions and correlations between results from 2930 files with no missing value. We give the frequency of results described as indicating a risk of first VTE or of VTE recurrence. We propose 2 quantitative scores linking the 12 parameters at the individual level and reflecting their degree of dispersion with respect to their mean, describe the values of these scores and their associations with thrombophilic results. CONCLUSIONS: These normal values should help laboratory workers to validate process results and to assess their degree of originality. Our 2 scores should help to determine the intra-patient plausibility of associations of results. The usefulness of these laboratory scores for predicting clinically-relevant outcomes deserves to be investigated.
INTRODUCTION: No reference values are currently available for coagulation assays performed for thrombophilia screening prescribed according to guidelines, after a first venous thromboembolic (VTE) event, and we have no idea of the intra-patient associations between results. METHODS: We performed a retrospective study of consecutive prescriptions fulfilling guidelines in a French university hospital from 2010 to 2019 (n = 3842) from the Glims® laboratory information system. We collected results of 12 parameters: aPTT, PT, fibrinogen (Fg), one-stage clotting methods for factors VIII, IX, XI and II (FVIII, FIX, FXI, FII), antithrombin (using an amidolytic assay: AT), protein C and S (using clotting assays: PC and PS) and mixing tests of a lupus-anticoagulant sensitive aPTT and of DRVVT. RESULTS: We show the results of the 12 parameters from 3603 individual files with less than 6 missing values, then describe these distributions and correlations between results from 2930 files with no missing value. We give the frequency of results described as indicating a risk of first VTE or of VTE recurrence. We propose 2 quantitative scores linking the 12 parameters at the individual level and reflecting their degree of dispersion with respect to their mean, describe the values of these scores and their associations with thrombophilic results. CONCLUSIONS: These normal values should help laboratory workers to validate process results and to assess their degree of originality. Our 2 scores should help to determine the intra-patient plausibility of associations of results. The usefulness of these laboratory scores for predicting clinically-relevant outcomes deserves to be investigated.