DiaPharma Group, Inc.

Ristocetin is a glycopeptide antibiotic isolated from Nocardia lurida that initiates binding of von Willebrand Factor (vWF) to platelet glycoprotein Ιb, resulting in platelet aggregation or agglutination. Ristocetin is widely used reagent as an agonist for in vitro testing of ristocetin-induced platelet aggregation which when impaired can be associated with von Willebrand disease, Bernard-Soulier Syndrome as well as other conditions. For labratory use only.

Use Ristocetin when:

• there is prolonged bleeding
• there is reduced factor VIII activity
• there is impaired platelet function
• there is a genetic history but no evidence of hemophilia
• to differentiate the types of VWD
• pre- and post-surgery
• in the differential diagnosis of hemophiliacs

Principle

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 paraformaldehyde.

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 hyperaggregation tendency. In addition, it serves n the diagnosis of platelet dysfunction due to deficiency of platelet surface glycoprotein Ib (Bernard-Soulier Syndrome).

Reagent -- Composition, Packaging, Storage and Stability

Ristocetin (Cat. No. B706-001 or 706-001), 6 x 100 mg vials. Ristocetin is provided in vials containing 100 mg of lyophilized material, and must be reconstituted with 0.85% saline before use. An appropriate amount of the lyophilized material can be weighed out and diluted in a glass vial if the entire 100 mg of ristocetin in the vial is not used at one time. Lyophilized ristocetin can be stored at room temperature until the expiration date printed on the vial. Once reconstituted, ristocetin is stable for 7 days when stored at 2 - 8ºC, or for 4 weeks if frozen and stored at -20ºC.