Preimplantation genetic testing laboratory classification strategies are associated with diagnostic yield and downstream clinical performance.

This retrospective cohort analysed 9,630 preimplantation genetic testing for aneuploidy (PGT-A) cycles performed between 2015 and 2023, i.e. 40,308 blastocysts biopsied at the trophectoderm and tested by next-generation sequencing in three commercial laboratories. Overall, 52.3% of blastocysts were euploid, but diagnostic yield differed between laboratories according to maternal age: Laboratory B had fewer euploid embryos in younger patients and more after 42 years, and Laboratory C had lower yield below 41 years. Among 7,333 single euploid embryo transfers, live birth rates were 49.8%, 41.6% and 50.7% for Laboratories A, B and C. After adjustment, Laboratory B remained associated with lower odds of live birth than Laboratory A (OR = 0.71; 95% CI 0.64-0.79), whereas Laboratory C was comparable (OR = 1.08; 95% CI 0.89-1.32).

Synthesis written by Geno'X. For the full original abstract, please refer to the source publication.

The study shows that a 'euploid embryo' does not carry the same value depending on the laboratory that classifies it, which questions the harmonisation of PGT-A classification strategies. The euploidy rate alone is therefore not enough to judge a laboratory, as the authors conclude. The retrospective design and the lack of detail on classification strategies in the abstract prevent identifying what drives the gap.

Analysis by Dr Thibaut Benquey