About Ristocetin
Ristocetin is a negatively charged antibiotic that induces platelet agglutination in vitro. Plasma vWF activity is determined by the ability of patient's plasma to support ristocetin-induced agglutination of normal formalin-fixed platelets. Reduced levels are characteristic of von Willebrand disease, in which factor VIII levels are usually reduced proportionately. Falsely elevated values may occur with stress, inflammation, pregnancy, estrogen therapy, or exercise. Values are also affected by ABO blood type, with type O averaging 15-30% lower than non-O.
Using  to Diagnose von Willebrand's Disease
In an unexplained way  / (ristocetin sulfate), a glycopeptide antibiotic isolated from Nocardia lurida, initiates binding of VWF to platelet glycoprotein Ib. Although the mechanism is not fully understood, has been widely used for IN VITRO testing of VWF function.
Two Associated Assays Exist:
RISTOCETIN COFACTOR ACTIVITY
This assay is important in the diagnosis of VWD. It determines the plasma VWF dependent agglutination using a standardized platelet preparation of either freeze-dried platelets or platelets fixed with formalin or para-formaldehyde.
RIPA
Another methodology, named the RISTOCETIN
Induced Platelet Agglutination (RIPA), is an overall assay of the RISTOCETIN
induced agglutination of the patient's own platelets and plasma. The major advantage of this test is in the detection of VWD cases with a hyper aggregation tendency. In addition, it serves in the diagnosis of platelet dysfunction due to deficiency of platelet surface glycoprotein Ib (Bernard-Soulier syndrome).
Testing For VWD Today - Is Enough Being Done?
A usual coagulation screen will probably include:
- Platelet Count
- Bleeding TIme
- PTT
For VWD patients, these screens are not sufficient!
In VWD, the platelet count could be normal, and the bleeding time and PTT could also be normal due to external factors such as stress or exercise temporarily elevating the factor VIII levels.
The solution is to use
If identifying sufferers from VWD is important, at least one of the based assays should be included as part of the initial screen for patients with any indications of a potential bleeding disorder and also as part of any pre-surgical bloodwork.
Use / (ristocetin sulfate)
When there is...
- prolonged bleeding.
- reduced factor VIII activity.
- impaired platelet function.
- a genetic history but no evidence of hemophilia.
To differentiate the types of VWD.
In pre- and post-surgery.
In the differential diagnosis of hemophiliacs.
On all new borns
For more information, or to order / (ristocetin sulfate), contact abp.
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Contact abp for the best pricing, now and in the future.
Cofactor Activity