A method (100) to collect and mix a determinate volume or weight of a hematic fluid for use in the field of medical blood transfusions comprises: starting transfer procedure (102), positioning sac and tube (104), starting the hematic fluid transfer (108) with starting mixing the hematic fluid contained in the sac, a first reading and display of the current volume or weight (110) of the hematic fluid contained in the sac, a first verification of flow rate control (112), a verification of the last fraction of volume or weight (116) to complete the final volume or weight provided in the sac for the hematic fluid transfer, stop of mixing (118), a second reading and display of the current volume or weight (120) of the hematic fluid contained in the sac, a second verification of flow rate control (122), a verification of the target volume or weight collected (126), the stoppage of the hematic fluid transfer (128) and the end of hematic fluid transfer procedure (130).
