JBRA Assist. Reprod. 2025;29(Suppl 1):22-22
POSTER PRESENTATION
doi: 10.5935/1518-0557.20250077

P-009. Remembering is living: The incidence of false-positives in PGT-A cannot be ignored

Jose G. Franco Jr.^1,2, Claudia G. Petersen^1,2, Laura D. Vagnini², Fabiana C. Massaro¹, Bruna Petersen¹, Andreia Nicoletti¹, Juliana Ricci¹, Camila Zamara¹, Renata A. Pouza¹, Bianca C. Matuella¹, Carla M.F. Dias¹, Elisangela V. Espirito Santo¹, Ana Clara A. Egydio¹, Joao Bosco Meziara¹, Joao Batista A. Oliveira^1,2

¹Center for Human Reproduction Prof. Franco Jr, Ribeirao Preto, Brazil
²Paulista Center for Diagnosis Research and Training, Ribeirao Preto, Brazil

Objective: In some countries, the use of PGT-A has become epidemic. The indications for PGT-A have increased from its use in a few cases to its use in all IVF cases. This indiscriminate use cannot be attributed solely to medical reasons but perhaps to hidden economic pressures since there are insufficient data to support the efficacy of PGT-A via Evidence-Based Medicine, which guides all other areas of medical science. An important issue is PGT-A false-positive diagnosis, with the consequent increased risk of absence of embryos for transfer and the need for more IVF cycles. The few studies on false-positive results have shown an incidence of 0-20%. Comparisons of false-positive results of PGT-A and the results of whole-embryo analysis are even more rare. This study aimed to analyse the agreement between the results of previous aneuploid embryo diagnosis by PGT-A and reanalysis of DNA obtained from whole embryos (gold standard).
Methods: This prospective study included a total of 53 blastocysts from 53 patients (age µ:37±3.6 years) vitrified on Day 5 that were previously biopsied for PGT-A. The most frequent indication for PGT-A was request by the patient. All these embryos were diagnosed with whole-chromosomal (n=47) or segmental chromosomal (n=6) aneuploidy in the last four years. The embryos were donated with informed consent by patients following the Human Medical Authority regulations. The blastocysts were thawed, transferred to PCR tubes and stored at -20°C until genetic analysis. The whole embryo was amplified via MALBAC^® technology (Yikon Genomics). The DNA concentration of the amplified product was measured with a Qubit 3.0 fluorometer (Thermo Fisher Scientific). The samples were subjected to next-generation sequencing (NGS) with the Illumina MiSeq^® System. The ploidy status results were obtained from ChromGo™software (Yikon Genomics).
Results: A total of 47 blastocysts were diagnosed with whole-chromosome aneuploidy. Reanalysis of DNA that was obtained from whole embryos identified a concordance rate of 80.9% (38/47) and discordance rate of 19.1% (9/47). On the other hand, concordance in diagnosis was observed in 50% (3/6) and discordance of diagnosis was observed in 50% (3/6) of the 6 blastocysts with partial aneuploidy. Table 1 shows the results.
Conclusion: The rate of discordance (false-positive) between the reanalysis of whole embryos and previous results of wholechromosomal aneuploidy (PGT-A) was 19.1%. Regarding segmental aneuploidy, the discordance was 50%. False-positives are a reality when PGT-A is used. It is important for IVF regulatory institutions to require an annual reanalysis of aneuploid embryos in each centre so that we can definitively reach a conclusion about how many normal embryos are discarded. The Code of Ethics appreciates your help.

 

Table 1. PGT-A X Whole Embryo: results.