After the ICSI process and under micromanipulation techniques, embryos on their third or fifth day of development are subjected to the extraction of 1 or 2 of their cells and then the nuclei are analyzed by marking their chromosomes with fluorescent probes or the DNA of these blastomeres is amplified and the genetic information is analyzed.
Meanwhile, the rest of the embryo remains in culture or is frozen for transfer as soon as the diagnosis is known.