PGT-A screens chromosome number
PGT-A examines a small sample of cells from an embryo to screen for gains or losses of chromosomes. It may be discussed in selected IVF situations, but it is not a universal test and does not diagnose every genetic condition.
Results can include euploid, aneuploid, mosaic or no-result findings. Because the sample comes from cells that form the placenta, it may not perfectly represent every cell in the embryo.
PGT-M looks for a known single-gene condition
PGT-M is designed for a family where a specific disease-causing gene change has been identified, such as certain inherited blood or metabolic conditions. It is targeted testing—not a general check for every disorder.
The genetics team usually needs reports from affected relatives or the intended parents and may need to develop a family-specific test before the IVF cycle begins.
The usual pathway
After counselling and test preparation, IVF is used to create embryos. Suitable embryos develop to the blastocyst stage, a small cell sample is taken, and embryos are commonly frozen while an accredited genetics laboratory performs testing.
- Clinical and genetic counselling
- IVF, fertilisation and embryo culture
- Blastocyst biopsy by an experienced embryology team
- Laboratory analysis and a written result
- Review of suitable embryos and a transfer plan
Understand the limits before consenting
Testing may leave no embryo suitable for transfer, and some embryos may return an uncertain or no-result finding. Biopsy and freezing are highly specialised procedures and are not completely risk-free.
Prenatal testing may still be offered after pregnancy because PGT is not a guarantee. Decisions about mosaic or uncertain results require individual genetic and clinical counselling.