What does a von Willebrand factor antigen level of 180% mean?

Interpretation of von Willebrand Factor Antigen Level of 180%

A von Willebrand factor antigen (VWF:Ag) level of 180% is within the normal reference range (50-217%) and does not indicate von Willebrand disease (VWD). 1

Understanding VWF:Ag Levels

• VWF:Ag is a laboratory measurement that quantifies the amount of von Willebrand factor protein in plasma, with normal values typically ranging from 50-200% 1
• Your result of 180% falls within the normal range, indicating adequate levels of von Willebrand factor protein 1
• Normal VWF:Ag levels generally exclude the diagnosis of type 1 and type 3 VWD, which are characterized by reduced or absent VWF protein 1

Clinical Significance of Normal-High VWF:Ag Levels

• VWF:Ag levels in the upper normal range (like 180%) may reflect:

  • Normal physiological variation, especially in individuals with non-O blood groups 2
  • Acute phase reaction in response to inflammation, infection, or recent surgery 2
  • Possible elevation due to stress, pregnancy, or exercise 2

• Elevated VWF:Ag levels (>200%) have been associated with:

  • Advanced liver disease 3
  • Malignancies, including breast cancer 4
  • Inflammatory conditions 2

Important Considerations

• VWF:Ag measurement alone is insufficient to diagnose or exclude all types of VWD 1
• Type 2 VWD (qualitative defects) may present with normal VWF:Ag levels but abnormal function 1, 5
• For complete VWD assessment, additional tests are typically needed:
  • VWF ristocetin cofactor activity (VWF:RCo) to assess function 1, 6
  • VWF:RCo/VWF:Ag ratio to distinguish between type 1 and type 2 VWD 1
  • VWF multimer analysis in suspected type 2 VWD 2, 5

Clinical Interpretation

• A VWF:Ag level of 180% effectively rules out type 1 and type 3 VWD 1

• If there is clinical suspicion of a bleeding disorder despite normal VWF:Ag:

  • Consider type 2 VWD variants that may have normal antigen levels but functional defects 5
  • Evaluate VWF:RCo/VWF:Ag ratio (ratio <0.5-0.7 suggests type 2 VWD) 1
  • Consider specialized testing such as RIPA (ristocetin-induced platelet aggregation) for type 2B VWD 5

• Laboratory testing for VWD has relatively high coefficients of variation (10-30%), which should be considered when interpreting borderline results 2