Von Willebrand-Jürgens factor (vWF; synonyms: Clotting factor VIII-associated antigen or von Willebrand factor antigen, vWF:Ag) is an adhesive glycoprotein (macromolecules consisting of a protein and one or more covalently bound carbohydrate groups (sugar groups)) that plays an important role in hemostasis (blood clotting). It is involved in primary and secondary hemostasis. In primary hemostasis, it contributes to the adhesion (“adherence”) of platelets (blood cells) to the injuredsubendothelium (subendoethelial matrix; endothelium: layer of endothelial cells lining the interior of blood vessels) is involved in platelet aggregation (pooling of platelets).Furthermore, vWF is a carrier protein for factor VIII.
The procedure
Material needed
- Citrate plasma, frozen (by transport service; no mailing).
Preparation of the patient
- Not required
Disruptive factors
- Not known
Standard values
| Reference range (in %) | |
| Newborn | 30-70 |
| Infants | 100-140 |
| Adults | 50-160 |
Von Willebrand factor activity (factor VIII ristocetin cofactor): 50-150%.
Indications
- V. a. coagulation disorders in factor VIII C deficiency or prolonged bleeding time.
- Unclear bleeding
- Prolonged bleeding time (in the absence of medication, e.g., acetylsalicylic acid, ASA).
Interpretation
Interpretation of increased values
- Age
- Infections, unspecified
- Surgeries, unspecified
- Pregnancy
- Stress
- Vasculitis (inflammation of the blood vessels)
Interpretation of decreased values
- Von Willebrand-Jürgens syndrome – most common congenital disease with increased bleeding tendency.
- Blood group 0 (in up to 35%).
- Endocarditis (inflammation of the inner lining of the heart)
- Heart defect, unspecified
- Hypothyroidism (underactive thyroid gland)
- Myeloproliferative syndrome (progressive disease of the blood system that leads to an increase in the cells of at least one row of cells at the beginning):
- Acute Di Guglielmo syndrome (erythremia).
- Chronic myeloid leukemia (CML)
- Essential thrombocythemia (ET) – chronic myeloproliferative disorder (CMPE, CMPN) characterized by chronic elevation of platelets (thrombocytes).
- Osteomyelofibrosis/osteomyelosclerosis (OMF or OMS).
- Polycythaemia vera (rubra) (PV)
- Therapy with valproate – antiepileptic drug (active substance used in epileptic seizures).
Notes
- If the result is abnormal, further tests such as collagen binding activity or vWF multimer analysis must follow