Lower Risk of Thrombosis in Blood Group O Patients: Are low clotting factor levels the reason?

Background: The ABO Blood group system has been evaluated many a times for increased risk of vascular accidents and heart diseases. This study aims to prove that the reason behind the decreased risk of thrombosis in O blood group population could be the decreased levels of clotting factors in its plasma compared to other blood groups. Objective: To assess the levels of clotting factors VII, VIII, IX and X in all blood groups to determine whether blood group O has the lowest levels of all clotting factors in its plasma. Methods: This is a Descriptive Cross sectional study, conducted at Dr. Ziauddin Hospital Karachi and Dow University of Health Sciences over a period of six months. The study involves 16 plasma units divided into four of each blood group. On the day of testing plasma was thawed and assays of factor VII, VIII, IX and X were performed on all blood groups and results noted. Results: Levels of Factor VIII, IX and X were found to be highest in blood group AB and lowest in blood group O. Factor VII levels varied from others. Conclusion: Our results showed that factor VII levels vary in different blood groups, may be due to its short half-life. Thus we could not establish a link between ABO blood groups and clotting factor levels.