The present invention relates to a method comprising creating and maintaining a high vacuum environment inside the blood collection container has the effect of accelerating blood coagulation of a blood sample within said container, speeding up medical procedures dependent on fresh coagulated blood, and rapidly provides coagulated blood products effectively separated into blood serum and a blood clot absent of additives and contaminants which would make the blood unsuited for certain uses, such as blood banking and LeucoPatch®. The invention further relates to an apparatus and a kit suitable for accelerating blood coagulation in blood without requiring the use of additives.Thereby, a pure and uncontaminated coagulated autologous blood product is achieved from a blood sample significantly faster than previously possible. When drawing blood without anticoagulant additive, such as when taking serum samples or blood for LeucoPatch® preparation, it is crucial to achieve fibrin coagulation as rapidly as possible, not only to save time, but to increase the quality of the blood clot and plasma separation and so purity and quality, especially when the blood sample is taken form a patient on anticoagulant therapy drugs like Xarelto®.
