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Introduction: Thrombin generation assays (TGAs) assess the overall functionality of the hemostatic system and thereby provide a reflection of the hemostatic capacity of patients with disorders in this system. Currently, four (semi-)automated TGA platforms are available: the Calibrated Automated Thrombogram, Nijmegen Hemostasis Assay, ST Genesia and Ceveron s100. In this study, we compared their performance for detecting patients with congenital single coagulation factor deficiencies., Materials and Methods: Pooled patient samples, healthy control samples and normal pooled plasma were tested on all four platforms, using the available reagents that vary in tissue factor and phospholipid concentrations. The TGA parameters selected for analysis were peak height and thrombin potential. Results were normalized by using the calculated mean of healthy controls and a correction for between-run variation. Outcomes were presented as relative values, with the mean of healthy controls standardized to 100 %., Results: Across all platforms and reagents used, thrombin potentials and peak heights of samples with coagulation factor deficiencies were lower than those of healthy controls. Reagents designed for bleeding tendencies yielded the lowest values on all platforms (relative median peak height 19-32 %, relative median thrombin potential 19-45 %). Samples representing more severe coagulation factor deficiencies generally exhibited lower relative peak heights and thrombin potentials., Conclusions: Thrombin generation assays prove effective in differentiating single coagulation factor deficient samples from healthy controls, with modest discrepancies observed between the platforms. Reagents designed for assessing bleeding tendencies, featuring the lowest tissue factor and phospholipid concentrations, emerged as the most suitable option for detecting coagulation factor deficiencies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: There are significant differences in the activated partial thromboplastin time (APTT) critical values reported in different studies, most of which does not make recommendations for any specific clear detection systems. The International Council for Standardization in Hematology (ICSH) recommends that APTT critical values be established based on the reagent type, coagulation factor sensitivity and heparin response. The objective of this study was to establish APTT critical values by using different reagents and based on single coagulation factor deficiencies., Methods: The APTT values were determined in commercial endogenous coagulation factor-deficient plasma at concentrations of 1 IU/dL, 2 IU/dL, 5 IU/dL, 10 IU/dL, 20 IU/dL, and 30 IU/dL by using four assay systems. The retrospective collection of data from patients who lacked factor VIII (FVIII), FIX, or FXI alone was performed. Receiver operating characteristic (ROC) curves were constructed to assess the diagnostic accuracy of APTT for identifying patients with an endogenous coagulation factor activity < 5 IU/dL., Results: The APTT values in the plasma samples with the same concentrations of endogenous coagulation factors were significantly different among the four assay systems (P < 0.001). The suggested critical values of APTT were 40.0 s for Sysmex CS5100 (Actin FSL), 58.0 s for Sysmex CS5100 (Actin), 51.8 s for STA-R Evolution (STA-PTTA), and 64.8 s for ACL TOP 700 (HemosIL SynthasIL). On the basis of the ROC curve, the optimal threshold values for APTT (STA-PTTA) were 55.8 s in patients with a simple deficiency of FVIII (sensitivity = 100%, specificity = 85.7%, area under the ROC curve (AUC) = 0.982), 54.3 s in patients with a simple deficiency of FIX (sensitivity = 100%, specificity = 92.9%, AUC = 0.986), and 71.7 s in patients with a simple deficiency of FXI (sensitivity = 100%, specificity = 94.1%, AUC = 0.992), which were closer (difference of 0.6-2.5 s) to the cutoff points for commercial plasma at equal factor levels., Conclusions: APTT critical values need to be established for different reagents based on the presence of a single coagulation factor deficiency., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)