Comprehensive chromosome screening (CCS) is a method that is used for healthy embryo selection and provides effective results. Comprehensive chromosome screening is the scanning of embryos for all chromosomes in the cell by microarray technology in couples that are planned to undergo Preimplantation Genetic Diagnosis (PGD). Compared to the fluorescence in situ hybridization (FISH) technique, which is widely used in routine aneuploidy screening and allows a limited number of the chromosomes to be screened, the comprehensive chromosome screening (CCS) technique allows the full assessment of structural and numerical chromosomal abnormalities (aneuploidy/abnormal number of chromosomes). The embryos with aneuploidy are excluded from the treatment procedure and only healthy embryos that have the correct number of chromosomes are selected for embryo transfer.

Comprehensive chromosome analysis, which is a method that is performed before the transfer of embryos to the uterus in IVF applications, evaluates all 24 chromosomes in terms of any chromosomal abnormalities. Since the whole chromosome map of the embryos examined through this method can be seen, chromosomal disorders can be detected and unhealthy embryos (aneuploidy embryos) are not used for embryo transfer.

Compared to Aneuploidy Screening with PGT, the Advantages of Comprehensive Chromosome Screening
By collecting several cells, rather than one just cell, from embryos growing to the blastocyst stage (the 5th or 6th day of the embryo development);

• CCS makes it possible to understand which embryo has the highest implantation potential
• CCS allows observing the mosaicism level of the developing blastocyst.
• Since the cells are collected by using trophectoderm biopsy from the trophectoderm (outer part) of the embryo which will eventually form the placenta, the inner cell mass (ICM), which will eventually form the fetus, is not damaged.

It is not an easy process to analyze and evaluate all the chromosomes of a growing embryo. A certain time is required for this process. If the embryo is biopsied on the morning of the 5th day, the results of the genetic analysis can be available on the sixth day and fresh embryo transfer can be performed.