Turnaround times
The quoted turnaround time is from sample receipt in the laboratory, to results authorisation in the Laboratory Information Management system. The times do not include transport of specimen to the laboratory or the administrative process to print and post/email reports. Service users must allow for transport and reporting time when ordering tests.
Clinical background:
A von Willebrand Screen (VWS) consists of a range of tests designed to assess activity of the various functions of von Willebrand Factor in plasma. Factor VIII, vW Activity and vW Antigen, along with vW associated platelet function and vW multimeric analysis may all be performed.
Specimen container paediatric:
Light blue – sodium citrate x 2
Specimen container adult:
Light blue – sodium citrate x 2
Minimum volume paediatric:
2.6mL
Minimum volume adult:
5.4mL
Special requirements:
Tubes must be correctly filled to line, to ensure correct ratio of blood to anticoagulant, ensure adequate mixing.
Sample stability:
4 hrs
Transport requirements:
Samples should be transported to lab without delay
Availability:
All testing performed at RVI Haematology laboratory and available during routine hours, Monday to Friday. Testing is usually performed on a weekly basis, depending on batch size availability.
Freq analysis:
Weekly
Add on test:
[email protected] (external)
Quality assurance:
UK NEQAS Blood Coagulation
Reference ranges:
See individual tests
Other info:
A screen of tests aimed at diagnosis of von Willebrand Disease. Screen currently consists of: Coagulation ScreenFactor VIII Assayvon Willebrand factor antigen. Ristocetin co-factor Platelet aggregation using ristocetin vW multimeric structure