Yes, it is possible to freeze the embryos, thaw them and then do a biopsy to analyze them genetically. In any case, this is not usual. Generally, what is done is to leave the embryos in culture until the day of the biopsy, either on day 3 or day 5.
The protocol to follow will depend on each laboratory and the personal situation of the patients.
Read the full article on: What is the Preimplantation Genetic Diagnosis (PGD)? ( 53).

Andrea Rodrigo
Bachelor's Degree in Biotechnology from the Polytechnic University of Valencia. Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia along with the Valencian Infertility Institute (IVI). Postgraduate course in Medical Genetics.