Thermo Fisher Scientific has developed an advanced assay to qualify FBS for use with ESCs. This assay is designed to sustain undifferentiated ES cells while maintaining karyotype integrity, LIF responsiveness and pluripotency markers. ES Cell FBS Qualified, has proven applications in reprogramming, pluripotency marker maintenance, and PSC morphology maintenance. When compared to competing products, it shows superior performance with regard to morphology and maintenance of pluripotency. The stringency of this assay provides researchers with the highest quality FBS for use in ES cell culture.