From Hemophilia to Deep Venous Thrombosis Patient Samples: How to Perform an Easy Coagulometer Validation Process According to Available Guidelines.

Validation protocols for the evaluation of coagulometers are needed to help professionals select the most suitable system for their regular laboratory routines. The objective of this study was to show how high standard protocols for the coagulometer validation process can fit into the daily laboratory routine. For this study, 45 healthy individuals and 112 patient samples were analyzed. From the patient samples, 51 were investigated for deep venous thrombosis, 27 for coagulopathy, 19 for antivitamin K therapy, and 15 for hemophilia. For the assessment, the performance of the 3 coagulometers and 1 point-of-care device was considered. One of the coagulometers was a new acquisition evaluated for precision, linearity, throughput, and carryover in the first moment, and the new coagulometer was then compared with the other well-established equipment in the laboratory. In normal plasma, coefficient of variation was ≤1.8% for total precision in screening tests and ≤3.5% for within-run precision in specific assays. For prothrombin time/international normalized ratio, no significant difference was found when comparing methods. Our study showed how to compare the capacity of a reagent in order to discriminate patients with severe hemophilia from patients with moderated hemophilia, and the κ coefficient agreement was 0.669 (95% confidence interval: 0.3-1.0; P < .001). d-dimer evaluated in patients with deep venous thrombosis and controls showed a 20% discrepancy between the methods. In our experience across Latin America, the number of laboratories that has performed this process is limited. In this study, we demonstrated how to adapt the validation process for the hemostasis laboratory routine to help the professional chose the best and more suitable option.

Clinical implications of the detection of antibodies directed against domain 1 of ß2-glycoprotein 1 in thrombotic antiphospholipid syndrome.

INTRODUCTION: Antibodies directed against domain 1 of ß2 glycoprotein 1 (aß2GP1-Dm1) have been involved in the immunopathogenesis of antiphospholipid syndrome (APS). However, the clinical relevance of aß2GP1-Dm1 in thrombotic APS has not yet been fully explored. OBJECTIVES: To determine the frequency of aß2GP1-Dm1 in a cohort of patients with thrombotic APS, and to evaluate whether testing for aß2GP1-Dm1 could have a clinical impact upon the risk assessment of the disease. METHODS: Patients were tested for aß2GP1-Dm1 antibodies by chemiluminescence (BioFlash/AcuStar®, ES). The presence of aß2GP1-Dm1 was evaluated in different clinical presentations of the disease. RESULTS: Eight-four patients with a history of venous or arterial thrombosis were included. Forty-five (54%) patients had aß2GP1 antibodies and 40% of them were positive for aß2GP1-Dm1. Levels of aß2GP1-Dm1 were higher in patients with systemic autoimmune disease (AUC=0.665; 95% CI=0.544-0.786; P=0.01), positive antinuclear antibody (AUC=0.654; 95% CI=0.535-0.772; P=0.01), triple antiphospholipid antibody (aPL) positivity (AUC=0.680; 95% CI=0.534-0.825; P=0.02) and positive lupus anticoagulant (AUC=0.639; 95% CI=0.502-0.776; P=0.07). In this cohort, aß2GP1-Dm1 antibodies were not associated with the site of the first thrombosis (OR=0,62, 95% CI=0.20-1.94, P=0.42), thrombosis recurrence (OR=1.0, 95% CI=0.37-2.71, P=1.0) or pregnancy morbidity (OR=1.5, 95% CI=0.33-7.34, P=0.58). In multivariate analysis, positivity for aß2GP1-Dm1 antibodies was associated with the diagnosis of systemic autoimmune disease (OR=4.01, 95% CI=1.14-14.2; P=0.03) and triple aPL positivity (OR=3.59, 95% CI=0.87-14.85; P=0.07). CONCLUSIONS: In the present cohort of thrombotic-APS patients, aß2GP1-Dm1 antibodies were related to the diagnosis of systemic autoimmunity and complex serological profile of the disease, as triple aPL positivity and positive antinuclear antibody. Thus, our results suggest that testing for aß2GP1-Dm1 antibodies may be useful for improving APS risk assessment.