Abstract:Human embryonic stem cells (hESCs) can proliferate without limit and differentiate into almost all cell lineages of three germ layers in vitro， thus holding tremendous potentials in developing stem cell-based medicinal products. Currently， the hESCs maintaining undifferentiated with complete differentiation potentials within certain propagation passage is regarded as ‘seed cells’， which are used as starting material in the induced differentiation into various terminal function cells or progenitors of the function cells according to different clinical indications. Thus， to ensure the success of induced differentiation， safety， and effectiveness in clinical applications， the ‘seed cells’ must not only exhibit unambiguous cell identity， ‘stemness’ and full differentiation potential， but also be free from microbiological contamination during the entire preparation process. All of these in fact represent the key quality attributes of the ‘seed cells’， and should be comprehensively assessed in the quality control tests during， or at the end of， the ‘seed cell’ preparation. In this paper， with our own experiences in quality assessment of hESC‘seed cells’， we discussed the key quality attributes of the ‘seed cells’as well as the proposed standards of each attribute with a goal of establishing a comprehensive quality assessment system for hESC ‘seed cells’in China.