Abstract: A new way of establishing clinical-grade exosome banks includes breakthroughs on three fundamental pre-requisite criteria. These three breakthroughs are developing a novel protocol for isolating exosomes, developing a simple and rapid test to predict potency, and using a novel cryoprotectant solution, trehalose solution, to store exosomes. Conditioned media culture is clarified using the SYR2-U20 KR2i automated TFF system. The culture then undergoes two distinct concentration processes, after which the exosomes can be concentrated into 1 ml. Furthermore, a simple and rapid test can predict the potency of mesenchymal stem cell, derived exosomes in T cell suppression assay. A higher percentage of CD90 has been found to be correlated with higher suppression activity. These tests can be used for quality controls in clinical trial. Furthermore, the usage of trehalose solution increases the stability of exosomes and keeps their potencies over long periods of time.