What is ristocetin cofactor test?
A von Willebrand factor (vWF) activity – ristocetin (riss-teh-SEE-tin) cofactor test lets doctors see how a protein called von Willebrand factor is working. The body’s clotting factors work together in a special order, almost like pieces of a puzzle. When the last piece is in place, the clot develops.
How does ristocetin cofactor assay work?
Ristocetin cofactor assay uses the patient’s platelet poor plasma (with vWF but no platelets) and adds ristocetin and exogenous formalin-fixed platelets which can passively agglutinate (but not actively aggregate, as they are dead).
What is the ristocetin test used for?
Ristocetin-induced platelet aggregation (RIPA) is used as an in vitro test to determine the presence and integrity of the platelet glycoprotein (GP) Ibα-V-IX complex and von Willebrand factor (VWF) interaction and is usually performed using platelet-rich plasma (PRP).
What is the best test to diagnose von Willebrand’s disease?
Prothrombin Time (PT) Test It measures primarily the clotting ability of factors I (1), II (2), V (5), VII (7), and X (10). If the level of any one of these factors is too low, it will take longer than normal for the blood to clot. The results of this test will be normal among most people with VWD.
Is Humate P A blood product?
As Humate P® is a plasma product there is a risk for transmission of infection. Humate P® should be given to a pregnant woman only if clearly needed. prescribed therapy.
What is Type 2B VWD?
Type 2B von Willebrand disease (VWD) is an inherited bleeding disorder caused by changes in von Willebrand factor (VWF) that enhance binding of VWF to GPIb on platelets.
What causes VWD?
VWD is caused by a defect or deficiency in von Willebrand Factor (VWF), a large protein made up of multiple subunits. VWF binds to clotting factor VIII in the circulation and protects it from being broken down. VWF also helps platelets bind to the inside of injured blood vessels.
What is humate-P for?
Humate-P, Antihemophilic Factor/von Willebrand Factor Complex (Human), is indicated for treatment and prevention of bleeding in adults with hemophilia A (classical hemophilia).
What are the results of the ristocetin cofactor test?
Ristocetin cofactor is useful in assessing binding of von Willebrand Factor to platelet factor GP1b. When combined with other tests, results are useful in categorizing the type of von Willebrand disease.
What is ristocetin cofactor for von Willebrand disease?
Ristocetin Cofactor – von Willebrand disease is the most common hereditary bleeding disorder. von Willebrand Factor is necessary for platelet adhesion to injured endothelium. Ristocetin cofactor is useful in assessing binding of von Willebrand Factor to platelet factor GP1b.
When to use the von Willebrand factor cofactor assay?
If von Willebrand factor activity is less than 55%, then the von Willebrand factor ristocetin cofactor activity assay will be performed at an additional charge. Indicates the status of NY State approval and if the test is orderable for NY State clients.