|
Coagulation Test
Blood clotting tests are the tests used for diagnostics of the hemostasis system. Coagulometer is the medical laboratory analyzer used for testing of the hemostasis system. Modern coagulometers realize different methods of activation and observation of development of blood clots in blood or in blood plasma. Classification of blood clotting tests Substantially all coagulometers used in laboratory diagnostics are based on the methods of testing of the hemostasis system created more than fifty years ago. The majority of these methods are good to detect defects in one of the hemostasis components, without diagnosing other possible defects. Another problem of the actual hemostasis system diagnostics is the thrombosis prediction, i.e. sensitivity to the patient's prethrombotic state. All the diversity of clinical tests of the blood coagulation system can be divided into 2 groups: global (integral, general) tests, and «local» (specific) tests. Global tests Global tests, also known as gl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemostasis
In biology, hemostasis or haemostasis is a process to prevent and stop bleeding, meaning to keep blood within a damaged blood vessel (the opposite of hemostasis is hemorrhage). It is the first stage of wound healing. This involves coagulation, which changes blood from a liquid to a gel. Intact blood vessels are central to moderating blood's tendency to form clots. The endothelial cells of intact vessels prevent blood clotting with a heparin-like molecule and thrombomodulin, and prevent platelet aggregation with nitric oxide and prostacyclin. When endothelium of a blood vessel is damaged, the endothelial cells stop secretion of coagulation and aggregation inhibitors and instead secrete von Willebrand factor, which initiate the maintenance of hemostasis after injury. Hemostasis involves three major steps: * vasoconstriction * temporary blockage of a hole in a damaged blood vessel by a platelet plug * blood coagulation (formation of fibrin clots) These processes seal the injury or ho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrombosis
Thrombosis (from Ancient Greek "clotting") is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (thrombocytes) and fibrin to form a blood clot to prevent blood loss. Even when a blood vessel is not injured, blood clots may form in the body under certain conditions. A clot, or a piece of the clot, that breaks free and begins to travel around the body is known as an embolus. Thrombosis may occur in veins (venous thrombosis) or in arteries (arterial thrombosis). Venous thrombosis (sometimes called DVT, deep vein thrombosis) leads to a blood clot in the affected part of the body, while arterial thrombosis (and, rarely, severe venous thrombosis) affects the blood supply and leads to damage of the tissue supplied by that artery (ischemia and necrosis). A piece of either an arterial or a venous thrombus can break off as an embolus, which could ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Coagulation Assay
Blood clotting tests are the tests used for diagnostics of the hemostasis system. Coagulometer is the medical laboratory analyzer used for testing of the hemostasis system. Modern coagulometers realize different methods of activation and observation of development of blood clots in blood or in blood plasma. Classification of blood clotting tests Substantially all coagulometers used in laboratory diagnostics are based on the methods of testing of the hemostasis system created more than fifty years ago. The majority of these methods are good to detect defects in one of the hemostasis components, without diagnosing other possible defects. Another problem of the actual hemostasis system diagnostics is the thrombosis prediction, i.e. sensitivity to the patient's prethrombotic state. All the diversity of clinical tests of the blood coagulation system can be divided into 2 groups: global (integral, general) tests, and «local» (specific) tests. Global tests Global tests, also known as gl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
D-dimer
D-dimer (or D dimer) is a fibrin degradation product (or FDP), a small protein fragment present in the blood after a blood clot is degraded by fibrinolysis. It is so named because it contains two D fragments of the fibrin protein joined by a cross-link, hence forming a protein dimer. D-dimer concentration may be determined by a blood test to help diagnose thrombosis. Since its introduction in the 1990s, it has become an important test performed in people with suspected thrombotic disorders, such as venous thromboembolism. While a negative result practically rules out thrombosis, a positive result can indicate thrombosis, but does not exclude other potential causes. Its main use, therefore, is to exclude thromboembolic disease where the probability is low. D-dimer levels are used as a predictive biomarker for the blood disorder, disseminated intravascular coagulation and in the coagulation disorders associated with COVID-19 infection. A four-fold increase in the protein is an ind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood Plasma
Blood plasma is a light amber-colored liquid component of blood in which blood cells are absent, but contains proteins and other constituents of whole blood in suspension. It makes up about 55% of the body's total blood volume. It is the intravascular part of extracellular fluid (all body fluid outside cells). It is mostly water (up to 95% by volume), and contains important dissolved proteins (6–8%; e.g., serum albumins, globulins, and fibrinogen), glucose, clotting factors, electrolytes (, , , , , etc.), hormones, carbon dioxide (plasma being the main medium for excretory product transportation), and oxygen. It plays a vital role in an intravascular osmotic effect that keeps electrolyte concentration balanced and protects the body from infection and other blood-related disorders. Blood plasma is separated from the blood by spinning a vessel of fresh blood containing an anticoagulant in a centrifuge until the blood cells fall to the bottom of the tube. The blood plasma is t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platelet
Platelets, also called thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are a component of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping, thereby initiating a blood clot. Platelets have no cell nucleus; they are fragments of cytoplasm that are derived from the megakaryocytes of the bone marrow or lung, which then enter the circulation. Platelets are found only in mammals, whereas in other vertebrates (e.g. birds, amphibians), thrombocytes circulate as intact mononuclear cells. One major function of platelets is to contribute to hemostasis: the process of stopping bleeding at the site of interrupted endothelium. They gather at the site and, unless the interruption is physically too large, they plug the hole. First, platelets attach to substances outside the interrupted endothelium: ''adhesion''. Second, they change shape, turn on receptors and secrete chemical messengers: ''activatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thromboelastography
Thromboelastography (TEG) is a method of testing the efficiency of blood coagulation. It is a test mainly used in surgery and anesthesiology, although increasingly used in resuscitations in Emergency Departments, intensive care units, and labor and delivery suites. More common tests of blood coagulation include prothrombin time (PT) and partial thromboplastin time (aPTT) which measure coagulation factor function, but TEG also can assess platelet function, clot strength, and fibrinolysis which these other tests cannot. Thromboelastometry (TEM), previously named rotational thromboelastography (ROTEG) or rotational thromboelastometry (ROTEM), is another version of TEG in which it is the sensor shaft, rather than the cup, that rotates. Mechanics A small sample of blood is taken from the selected person and rotated gently through 4º 45', six times a minute, to imitate sluggish venous flow and activate coagulation. The clot forms around a thin wire probe used for measurement. The sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrombin Generation Assay
A thrombin generation assay (TGA) or thrombin generation test (TGT) is a global coagulation assay (GCA) and type of coagulation test which can be used to assess coagulation and thrombotic risk. It is based on the potential of a plasma to generate thrombin over time, following activation of coagulation via addition of phospholipids, tissue factor, and calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to .... The results of the TGA can be output as a thrombogram or thrombin generation curve using computer software with calculation of thrombogram parameters. TGAs can be performed with methods like the semi-automated calibrated automated thrombogram (CAT) (2003) or the fully-automated ST Genesia system (2018). TGAs were first used as manual assays in the 1950s and have since become in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endogenous Thrombin Potential
A thrombin generation assay (TGA) or thrombin generation test (TGT) is a global coagulation assay (GCA) and type of coagulation test which can be used to assess coagulation and thrombotic risk. It is based on the potential of a plasma to generate thrombin over time, following activation of coagulation via addition of phospholipids, tissue factor, and calcium. The results of the TGA can be output as a thrombogram or thrombin generation curve using computer software with calculation of thrombogram parameters. TGAs can be performed with methods like the semi-automated calibrated automated thrombogram (CAT) (2003) or the fully-automated ST Genesia system (2018). TGAs were first used as manual assays in the 1950s and have since become increasingly automated. Parameters Thrombogram parameters for the TGA include: * Lag time (minutes; time until thrombin first generated/thrombin concentration first increased) * Time to peak or ttPeak (minutes; time to maximum concentration of throm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ETP-based Activated Protein C Resistance Test
The activated protein C resistance (APCR) test is a coagulation test used in the evaluation and diagnosis of activated protein C (APC) resistance, a form of hypercoagulability. Hereditary APC resistance is usually caused by the factor V Leiden mutation, whereas acquired APC resistance has been linked to antiphospholipid antibodies, pregnancy, and estrogen therapy. APC resistance can be measured using either an activated partial thromboplastin time (aPTT)-based test or an endogenous thrombin potential (ETP)-based test. Methodology The aPTT-based APC resistance test involves a modified aPTT test performed in the presence and absence of activated protein C (APC). The ratio of these aPTT values is calculated and is called the APC sensitivity ratio (APCsr) or simply APC ratio (APCr). This ratio is inversely related to the degree of APC resistance. The ETP-based APC resistance test involves the addition of APC to a thrombin generation assay (TGA). This results in an inhibition of throm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrombodynamics Test
Thrombodynamics test is a method for blood coagulation monitoring and anticoagulant control. This test is based on imitation of coagulation processes occurring ''in vivo'', is sensitive both to pro- and anticoagulant changes in the hemostatic balance. Highly sensitive to thrombosis. The method was developed in the Physical Biochemistry Laboratory under the direction of Prof. Fazly Ataullakhanov. Technology description Thrombodynamics designed to investigate the ''in vitro'' spatial-temporal dynamics of blood coagulation initiated by localized coagulation activator under conditions similar to the conditions of the blood clotting'' in vivo''. Thrombodynamics takes into account the spatial heterogeneity trombodinamiki processes in blood coagulation. The test is performed without mixing in a thin layer of plasma Plasma or plasm may refer to: Science * Plasma (physics), one of the four fundamental states of matter * Plasma (mineral), a green translucent silica mineral * Quark–gl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overall Hemostatic Potential
The overall hemostatic potential (OHP) test is a global coagulation assay which can be used to measure coagulation. The OHP assay measures total fibrin generation in the presence of thrombin or tissue factor and tissue plasminogen activator (t-PA). It generates a fibrin time curve through the use of optical density measurement. This curve represents the balance between fibrin formation induced by thrombin or tissue factor and fibrinolysis induced by t-PA. The assay provides three parameters: overall coagulation potential (OCP), overall hemostatic potential (OHP), and overall fibrinolytic potential (OFP). OHP is the main parameter, while OCP and OFP are supplementary parameters to assess coagulation and fibrinolysis. One further parameter, clot lysis time (CLT), can also be determined. The OHP assay measures the integrated effect of procoagulant, anticoagulant, and fibrinolytic factors. The OHP is a technically simple but relatively labor-intensive assay. As of 2010, it had been i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
