The present invention provides a method for preparing a cell culture medium comprising a mixture of blood products from two or more donors, comprising the steps of: a) providing at least a first blood product from a first donor； b) measuring the concentration of at least one quality factor in the first blood product； c) comparing the measured concentration of a quality factor to a concentration range predefined for the quality factor； d) selecting the first blood product for the cell culture medium if the concentration measured for the quality factor is in the predefined range and optionally converting the first selected blood product into a first processed blood product or else unselecting the first blood product.
