In an unexplained way RISTOCETIN, a glycopeptide antibiotic isolated from Norcadia lurida, initiates binding of VWF to platelet glycoprotein Ib. Although the mechanism is not fully understood, RISTOCETIN has been widely used for IN VITRO testing of VWF function.

Two Ristocetin 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 RISTOCETIN
 

If identifying sufferers from VWD is important, at least one of the Ristocetin 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
 

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