Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology 1 article published in JoVE Genetics Chromosome Screening of Human Preimplantation Embryos by Using Spent Culture Medium: Sample Collection and Chromosomal Ploidy Analysis Jin Huang*1,2,3,4, Yaxin Yao*5, Jialin Jia1,2,3,4, Xiaohui Zhu1,2,3,4, Jieliang Ma5, Jing Wang5, Ping Liu1,2,3,4, Sijia Lu5 1Centre for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, 2National Clinical Research Center for Obstetrics and Gynecology(Peking University Third Hospital), 3Ministry of Education, Key Laboratory of Assisted Reproduction (Peking University), 4Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, 5Department of Clinical Research, Yikon Genomics Co. Ltd. The present study reports a protocol for chromosome screening of human embryos that uses spent culture medium, which avoids embryo biopsy and enables chromosome ploidy identification using NGS. The present article presents the detailed procedure, including the preparation of culture medium, whole genome amplification (WGA), next-generation sequencing (NGS) library preparation, and data analysis.