There is no difference, it is the same name and what it used to be called as well as the more modern name. We used to call it PGS, preimplantation genetic screening, now we call it preimplantation genetic testing for aneuploidy. However what is different is the technique and both the techniques of the biopsy and genetic analysis have changed. I was involved in this, in previous years and due to my experience I had the privilege of going through these techniques that require more skill such as fixation of cells. We used to test only one cell on day 3, one blastomer on day 3, this caused a lot of problems and we used to only analyse genetically from nine to thirteen chromosomes. Nowadays we do cubing, it is better than fixation, we don’t use loose chromatin or DNA and we analyse the complete set of chromosomes, so twenty three pairs so we have evolved. PGT and PGTA are far better than PGS but it is the same name for the same process.
