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Background/Aims Traditionally used laboratory methods, i.e. one-stage or chromogenic assays for FVIII activity determination do not always and accurately reflect bleeding severity in haemophilia A (HA) patients. As global haemostasis assays provide overall haemostatic status estimation, we investigated the ability of three global assays for identifying bleeding phenotype both in severe and non-severe HA patients, as well as their usefulness in laboratory management of HA patients with discrepant bleeding phenotype. Materials and Methods Overall haemostasis potential (OHP), aPTT-clot waveform analysis (aPTT-CWA), endogenous thrombin potential (ETP) and FVIII activity were measured in 30 severe and 32 non- severe HA patients and 27 male controls. For classification of HA patients regarding bleeding phenotype, we used a scoring method that included three clinical parameters: age at first joint bleed, number of target joints and number of joint/muscle bleeds per year. Bleeding scores ≤4 and ≥5 suggested mild and severe beeding phenotype, respectively. Results All global assays correlated significantly with FVIII activity (P

Hemophilia A has been considered as a bleeding disorder that is not only a consequence of the defect in the coagulation system, but also of the impaired down-regulation of the fibrinolytic system. To examine correlation between activities and/or concentrations of most important fibrinolytic parameters with overall hemostasis potential (OHP) and fibrin clot permeability (FCP) in hemophilia A patients. Activities of FXIII, plasminogen, plasmin inhibitor, plasminogen activator inhibitor–1 (PAI-1) (Siemens Healthcare Diagnostics, Germany) and thrombin-activatable fibrinolysis inhibitor (TAFI) (Diagnostica Stago, France), as well as activated/inactivated TAFI antigen (TAFIa/ai) (Diagnostica Stago) and prothrombin fragment F1+2 concentrations (PF1+2) (Siemens) were tested in plasma samples of 63 hemophilia A patients (30 severe, 33 non-severe). OHP method, based on repeated spectrophotometric registration of fibrin-aggregation in plasma, after addition of small amounts of exogenous thrombin, tissue plasminogen activator and calcium, gave beside OHP parameter (area under the fibrin aggregation curve) 3 supplementary parameters: overall coagulation potential (OCP), overall fibrinolytic potential (OFP) and clot lysis time (CLT). Permeability coefficients (Ks), providing information on fibrin network porosity, were obtained by FCP method, flow measurement technique along with visualisation by electron microscopy scanning. Among fibrinolytic and OHP parameters significant but weak correlation (P< ; 0.05) was found only for OCP with TAFI and PF1+2 (r=0.252 and 0.266, respectively). Regarding FCP, significant correlation of Ks was found with FXIII, plasmin inhibitor and PF1+2 (r=-0.466, - 0.432 and -0.599, respectively). There was no correlation between Ks and OHP parameters. Obtained correlation between fibrinolytic parameters and parameters that assess coagulation activity and fibrin network porosity confirmed the association between these two processes in patients with hemophilia A.

Measurement of FVIII activity allows diagnosis of hemophilia A and categorization of disease severity, but has poor correlation with clinical phenotype. New laboratory methods that assess global hemostasis have been developed, with intention to better diagnose and monitor hemophilia A patients. To assess overall coagulation and fibrinolytic activity in hemophilia A patients using non- standard laboratory methods: overall hemostasis potential (OHP), aPTT-waveform analysis (aPTT- WA) and endogenous thrombin potential (ETP). Total of 63 hemophilia A patients (30 severe and 33 non-severe) and 27 healthy male subjects as control group were tested. OHP method, based on repeated spectrophotometric registration of the fibrin-aggregation in plasma, after addition of small amounts of exogenous thrombin, tissue-type plasminogen activator and calcium, provides besides OHP parameter (area under the fibrin aggregation curve) supplemetary parameters: overall coagulation potential (OCP), overall fibrinolytic potential (OFP) and clot lysis time (CLT). In-house aPTT- WA was performed on BCS with Actin FS (Siemens Healthcare Diagnostics, Germany), obtaining 3 quantitative waveform parameters from 2 different evaluation modes, drifting baseline (DB) and point of inflexion (PI): DELTA (aPTT- PI minus aPTT-DB), RATIO1 (aPTT- PI/aPTT-DB) and RATIO2 (DELTA/aPTT-DB). ETP method, setting C was performed on BCS-XP (Siemens), giving 4 parameters: area under the thrombin generation curve (AUC), peak thrombin concentration (Cmax), time to peak thrombin concentration (t- max) and time to signal beginning (t-lag). Obtained results revealed statistically significant difference (P< ; 0.05) for all parameters between analyzed groups, except for CLT between severe and non-severe group. Global assays can serve as a useful laboratory tool for assessing overall coagulation and fibrinolysis activity, providing at the same time additional information about hemophilia A patients.