International journal of laboratory hematology
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The use of adapted cut-off values in the elderly, combined with clinical probability (PTP), increases the proportion of patients in whom venous thromboembolism (VTE) can be safely excluded, compared with the conventional cut-off value of 500 μg/L fibrinogen equivalent units (FEU). We evaluated the clinical performance of three different approaches to establish cut-off values for a D-dimer assay whose results are expressed in D-dimer units (D-DU). ⋯ For the HemosIL D-dimer HS, the use of specific cut-off values in older subjects with suspected DVT and nonhigh PTP increases the number of patients in whom DVT can be safely excluded.
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Comparative Study
Comparison between thromboelastography and conventional coagulation tests after cardiopulmonary bypass surgery in the paediatric intensive care unit.
Following paediatric cardiac surgery using cardiopulmonary bypass (CPB), there is a risk of significant postoperative bleeding. A number of risk factors are associated with postoperative bleeding including; age, complexity of the surgery, dilution and consumption of clotting factors. We conducted a prospective audit comparing different coagulation tests used following paediatric CPB to determine whether thromboelastography (TEG) on the intensive care unit or routine laboratory coagulation assays including fibrinogen are better at assessing bleeding and bleeding risk. ⋯ Thromboelastography did not show better correlation with postoperative bleeding than conventional clotting tests. TEG parameter maximum amplitude correlates with platelet count and fibrinogen.
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Platelets are derived from megakaryocytes in the bone marrow that create the cellular machinery the platelet needs to participate in the different processes of primary hemostasis including adhesion, activation and clot formation at the site of injury. Defects related to megakaryocyte differentiation, platelet formation, and/or platelet function can result in bleeding. Patients with thrombopathies can present with mucous membrane bleeding but may also present with bleeding following trauma or surgery. ⋯ A major step forward was made during the last 3 years using new-generation genetic approaches that resulted in the discovery of novel genes such as NBEAL2, RBM8A, ACTN1, and GFI1B for the well-known IPD that cause gray platelet syndrome, thrombocytopenia-absent radius syndrome, and autosomal dominant thrombocytopenias, respectively. In the near future, it is expected that a similar approach will identify many novel genes that cause IPD of unknown etiology, which are common. The future challenge will be to use a functional, systems biology approach to study the genes mutated in IPD and determine their roles in megakaryocyte and platelet biology and pathology.
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Review Case Reports
Acquired hemophilia: a case report and review of the literature.
Acquired hemophilia A (AHA) is a rare bleeding disorder caused by autoantibodies against clotting factor VIII (FVIII). FVIII autoantibody is characterized as polyclonal immunoglobulin G directed against the FVIII procoagulant activity. This disease occurs most commonly in the elderly population and with preponderance of men in nonpregnancy-related AHA. ⋯ The principles of treatment consist in controlling the bleeding and eradicating the inhibitor. Because of the overall high relapse rate (15-33%), it is also recommended to follow up these patients. The review summarizes what is currently known about the epidemiology, pathogenesis, clinical features, diagnosis, treatment and prognosis of AHA and starts with a case report.
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Disseminated intravascular coagulation (DIC) is a condition in which systemic activation of coagulation without a specific localization occurs, resulting in extensive formation of intravascular fibrin, particularly in small and midsize vessels. Disseminated intravascular coagulation may lead to several altered coagulation parameters, including a low platelet count, abnormal global clotting assays, low levels of physiological anticoagulant proteases, or increased fibrin degradation products. Also, more complex assays for activation of coagulation factors or pathways may indicate involvement of these molecules in DIC. ⋯ Current insights on relevant etiological pathways that may contribute to the occurrence of DIC have led to innovative therapeutic and adjunctive approaches to patient with DIC. Management options directed at the amelioration of hemostatic activation may tentatively be indicated and were found to be advantageous in experimental and clinical investigations. These treatments encompass elimination of tissue factor-mediated thrombin generation or restitution of normal anticoagulant function.