<prompt> Answer this question truthfullyWhat are the laboratory results for Von Willebrand disease?  <response>: <reason> The diagnosis of von Willebrand disease VWD begins with a relevant personal or family history of mucocutaneous bleeding. When VWD is suspected, several levels of testing are needed in order to make diagnosis as shown below: Screening testing include the following 3 tests:vWF antigen vWF:Ag level Normal values are between 50 and 200 IUdL Levels below 50 are considered to be low Factor VIII activity FVIII:C Type 12 has somewhat lower levels of FVIII Type 3 has markedly reduced levels of FVIII vWFristocetin cofactor activity VWF:RCo as a measure of platelet-binding activity of vWF The normal range of VWF:RCo is 50 to 200 IUdLWhen the results of the screening tests are normal, the tests should be repeated, if values are at the low end of the normal range or if VWD is strongly suspected. If the screening tests reveal definitive abnormalities, a diagnosis of VWD can be made.A proportional decrease in von Willebrand factor antigen and von Willebrand factorristocetin cofactor activity fits the diagnosis of type 1 von Willebrands disease.These tests are required to determine the phenotypic characteristics that define types 2A, 2B, and 2M:VWF multimer distribution using gel electrophoresis Ristocetin -induced platelet aggregation RIPAA platelet aggregation assay will show an abnormal response to ristocetin with normal responses to the other agonists used. Type 2B can be distinguished by enhanced ristocetin-induced platelet aggregation in the presence of low-dose ristocetin. Type 2N can only be diagnosed by performing a factor VIII binding assay.Other tests performed in any patient with bleeding problems are:complete blood count shows normal platelets except in APTT activated partial thromboplastin time may be normal or prolonged prothrombin time is normal thrombin time fibrinogen level. Testing for factor IX may also be performed if hemophilia B is suspected.Other coagulation factor assays may be performed depending on the results of a coagulation screen.Patients with Von Willebrand disease will typically display a normal prothrombin time and a variable prolongation of partial thromboplastin time. 