ABO and Thromboembolism: The link between the ABO blood type and thromboembolic diseases and bleeding risk are intervened by the glycosyltransferase activity and plasma levels and biologic activity of vWF (Von Willebrand factor), a carrier protein for coagulation factor VIII which is low in O type.<h4>Conclusion</h4>Several studies related to the ABO phenotype show that genetically determined human ABO blood groups were correspondingly linked with an increased risk of various infectious and noninfectious diseases.