Inclusion Criteria:  Healthy male volunteers aged 18-30 years The American Society of Anaesthesiologists Physical Status (ASA PS) I risk class Must be able to give informed consent  Exclusion Criteria:  Female sex Blood type O A positive history of any acute diseases in the last four weeks Chronic diseases Any diagnosed haemostatic disorders History of anticoagulation Any known bleeding diathesis Any pharmacotherapy in the previous week Participants were informed about the prohibition of drinking alcohol, excessive exercise, and stress on the day before blood sampling