Von Willebrand factor levels in healthy blood donors and their association with blood group: A tertiary care hospital-based study.

Background: von Willebrand disease is a common inherited bleeding disorder caused by the deficiency of von Willebrand factor (vWF).^[1] The levels of vWF depend on several factors, including exercise, hormones, and ABO blood type.^[2] This study was planned to evaluate plasma vWF levels and factor VIII (fVIII) levels in healthy blood donors and its association with the ABO blood group.

Aims: The aim of this study was to evaluate plasma vWF levels and fVIII levels in healthy donors and its association with the ABO blood group.

Methods: This study was done in 2016 healthy adult blood donors. Complete history and relevant examination were done along with ABO and Rh (D) blood group typing, complete blood count, prothrombin time, activated partial thromboplastin time, vWF antigen (Ag) level, fVIII coagulant assay, and other tests for hemostasis.

Statistical analysis used: Data were expressed in proportions and mean, median, and standard deviation, respectively. An appropriate test of significance was applied. P < 0.05 was considered statistically significant.

Results and conclusions: vWF level of donors ranged from 24 to 186 IU/dL with a mean of 96.31 IU/dL. Low vWF Ag level (below 50 IU/dl) was found in 2.5% of donors while 0.1% (2/2016) had level <30 IU/dL. O Rh (D)-positive blood group donors had the lowest vWF level (87.85 IU/dL), while ARh (D)-negative donors had the highest vWF level (117.27 IU/dL). fVIII level of the donor population ranged from 22% to 174%, with a mean of 98.82%. About 2.48% of donors had fVIII levels below 50%. There was a statistically significant correlation between fVIII level and vWF level (P < 0.001).