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The PFA-100 (Platelet Function Assay [1] or Platelet Function Analyser [2]) is a platelet function analyser that aspirates blood in vitro from a blood specimen into disposable test cartridges through a microscopic aperture cut into a biologically active membrane at the end of a capillary.
The ristocetin-induced platelet aggregation (RIPA) is an ex vivo assay for live platelet function. It measures platelet aggregation with the help of von Willebrand factor (vWF) and exogenous antibiotic ristocetin added in a graded fashion. [ 1 ]
The PFA-100 (Platelet Function Assay — 100) is a system for analysing platelet function in which citrated whole blood is aspirated through a disposable cartridge containing an aperture within a membrane coated with either collagen and epinephrine or collagen and ADP. These agonists induce platelet adhesion, activation and aggregation, leading ...
Multiplate multiple electrode aggregometry (MEA) is a test of platelet function in whole blood. [1] [2] The test can be used to diagnose platelet disorders, [3] [4] [5] monitor antiplatelet therapy, [6] and is also investigated as a potential predictor of transfusion requirements and bleeding risk in cardiac surgery. [7]
Aspirin inhibits platelet function via the AA pathway while clopidogrel inhibits platelet function via the ADP pathway; thus, this test can be used to determine the degree to which a patient is anticoagulated due to either medication. In this assay, a standard TEG is run using patient's whole blood.
Bleeding time is a medical test done to assess the function of a person's platelets. It involves making a patient bleed, then timing how long it takes for them to stop bleeding using a stopwatch or other suitable devices. The term template bleeding time is used when the test is performed to standardized parameters.
The typical assays are not responsive for the effect of von Willebrand factor or platelet antagonists such as aspirin or thienopyridines (e.g. clopidogrel), and only supratherapeutic doses of GPIIb/IIIa antagonists may influence results. The sensitivity for coagulation factor deficiencies, including those induced by oral anticoagulation, is ...
In all forms of the ristocetin assay, the platelets are fixed in formalin prior to the assay to prevent von Willebrand's factor stored in platelet granules from being released and participating in platelet aggregation. Thus, the ristocetin cofactor activity depends only upon high-molecular multimers of the factor present in circulating plasma.