Mosaic PGT-A reports: laboratory thresholds and interpretation questions

A mosaic PGT-A report needs interpretation by the reporting laboratory and qualified clinical professionals. It is not a whole-embryo cell census or an automatic treatment instruction.

Report categories depend on the laboratory

Laboratories can use different thresholds and reporting policies for intermediate copy-number findings. ASRM’s 2023 committee opinion on mosaic PGT-A results (Fertility and Sterility 120:973–982) explains this variation. This source addresses reporting principles; it does not establish what most Thai laboratories do. This page therefore provides no universal low, medium or high percentage cut-offs.

Request the report’s own rules

• Which laboratory and assay produced this report?
• What are its validated reporting thresholds and limitations?
• Does it report mosaic findings, mask them or classify intermediate findings another way?
• How are segmental findings and no-result reports distinguished?
• Which clinician or qualified genetic counsellor will explain the actual finding and available options?

Keep interpretation separate from an individual decision

Do not treat a reported percentage as a measured proportion of abnormal cells throughout an embryo or as a personal fetal-risk percentage. Ask the professional team to explain uncertainty, its transfer policy and any pregnancy follow-up discussion using the complete report. A general article cannot decide embryo priority or whether transfer or additional testing is appropriate.

Information boundary: This is a planning aid. The treating clinician and laboratory explain medical findings, treatment and consent. Confirm current eligibility and administrative requirements with the responsible institution. This page does not assess an individual case.

Source checked 15 October 2026; professional guidance version 2023. No Thai laboratory prevalence or individual outcome estimate is asserted.