Von-Willebrand Screen

Pathology category

Haematology

Code

RAG

Referral code

Request form

Test information

Samples for patients aged <16 yrs old will be sent to Special Coagulation Department, Birmingham Children’s Hospital, Steelehouse Lane, Birmingham, B4 6NH Telephone: 0121 333 9999

Von-Willebrand Screen consists of:

Von-Willebrand Factor Antigen

Ristocetin co-factor

Factor VIII Assay (Discuss with laboratory if urgently required)

Guidelines

Pre-analytical

Sample transport should be at 4-25C and reach the laboratory ASAP

Please note: the samples must arrive within 4 hours of collection otherwise they will be rejected by the laboratory

Clotted and underfilled samples will be rejected by the laboratory

Reference range

Von-Willebrand Factor Antigen: 66-176 IU/dl

Ristocetin co-factor: 61-240 IU/dl

Factor VIII: 50-150 IU/dl

Tube type

Tube type info

3 x 2.7ml Blue top citrate

Special requirements

Minimum volume

3 tubes minimum 90% full (to the thick black line on the bottle) – essential to ensure 1:9 ratio of anticoagulant:blood

Assay frequency

Discuss with laboratory

TAT Inpatient (urgent)

Discuss with laboratory

TAT Inpatient

Approximately 4 weeks

TAT GP/Outpatient

Approximately 4 weeks

Referral lab

local and Special Coagulation Department, Birmingham Children's Hospital (if required)