How accurate is PGT-A?

Accurate enough to be useful, not accurate enough to be a diagnosis — and there is something specific you should ask your clinic. ESHRE recommends that published and in-house estimates of misdiagnosis rates should be available on request to prospective patients, along with pregnancy rates and live birth rates, so that consent to PGT is properly informed. So the question to ask is: what is your centre's own misdiagnosis rate? Not the manufacturer's figure, not a published average — the rate from your own laboratory's follow-up analysis. ESHRE recommends every centre calculates this, for each method used, and confirms diagnoses on a subset of embryos not transferred, precisely so this figure exists. If your clinic cannot give you that, it is reasonable to ask why. The main reasons a result can be wrong: The biopsy samples placental-lineage cells, which may not represent the whole embryo. Mosaicism — different cells having different chromosomes — can cause misinterpretation. Contamination, or DNA damage during biopsy, can affect reliability. The technology has limits: it cannot detect uniparental disomy, and it cannot always distinguish whether an abnormality arose before or after fertilisation. Because of all this, ESHRE recommends prenatal diagnosis is offered to every woman who becomes pregnant after PGT — not because the test is unreliable, but because it is a screening step rather than a final answer.