Eurofins Biomnis code

WILAG

Synonyms

• Von Willebrand antigen factor
• von Willebrand factor
• VWF:Ag

Specialty

Haematology

Clinical significance

Von Willebrand's disease is a congenital hemorrhagic diathesis due to either reduced expression of von Willebrand's factor or expression of a non-functional form of this factor. The disease is characterized by an increased bleeding time, a prolonged partial activated thromboplastin time and excessive mucosal and cutaneous hemorrhage following minor injury. The relevant tests to be performed are quantitative assays of Factor VIII and von Willebrand Factor levels and a functional assay of von Willebrand Factor activity. These tests cannot be performed in patients with ongoing inflammatory processes or in pregnant women. Moreover, the patient's blood group must be taken into account because normal Group O subjects habitually have lower levels of von Willebrand's Factor than others. According to the recommendations of the NABM, only the activity of von Willebrand factor and the coagulating activity of factor VIII are carried out in the 1st intention. The Willebrand factor antigen is only added if the activity of the von Willebrand factor and / or the activity of the factor VIIII is low, in the event of suspicion of von Willebrand disease or in the context of a family investigation.

Preanalytics

• 2 mL :
• Citrated Plasma
•   FROZEN
• Freezing within 4 hours

• A tube specifically for this analysis : No

Further information

Enclose the specific clinical information form (R5-INTGB : Haemostasis)
Plasma with platelets removed by double centrifugation: 2500 g 15 min
Send us the ABO blood group result. For desmopressin testing (Octim®, Minirin®) please indicate the time period for each tube (T0, T+1hr etc.)
Could you please provide the us the PFA-100 result, if available
It is advisable to send us a frozen and centrifuged citrate sample in compliance with the GFHT pre-analytical recommendations.

Documents to download

• Specific clinical information form (R5-INTGB)

Methodology

Immunological turbidimetric method

Turnaround time

1 day