Learn more about PGT

After patiently waiting for your Preimplantation Genetic Testing for Aneuploidy (PGT-A) results, you finally receive that message that they are available! 

You may be receiving these results from your clinical team or from your RGI genetic counselor.  This guide is to help you interpret your results.

When you review your results, you may recall that we use a technology called Next-Generation Sequencing (NGS) to evaluate the embryo for chromosomal abnormalities, or aneuploidy. Therefore, your PGT-A results will provides you information about the chromosome content of IVF embryos submitted to our lab for testing. Your physician will use these results to help select the embryo most likely to lead to a successful pregnancy.

Your report will include a summary of results for each embryo biopsy sample submitted for testing. The first number in the report represents the total chromosome count, followed by sex chromosomes, followed by abnormality or normal chromosome count.

As a reminder, chromosomes are inherited in pairs; one copy of each pair comes from the egg and one copy of each pair comes from the sperm. The autosomes, are the first 22 pairs of chromosomes. The 23rd pair of chromosomes are the sex chromosomes. Individuals with two X chromosomes are chromosomally female and individuals with one X and Y chromosomes are chromosomally male.

As you review your results, please keep in mind the following points:

  • Our report will include chromosomal sex information, unless we received a request to mask this information. 
  • You may find that you have an embryo or several embryos that have an aneuploid result. It’s important to keep in mind that all couples are at risk for producing chromosomally abnormal embryos and at any female age1, 2.
  • You may also find that you have an embryo that has an intermediate result or is classified as mosaic. Preimplantation genetic mosaicism is not thought to be related to maternal/egg donor age, and the clinical impact of a mosaic embryo varies2.
  • Based on the finding, some results may include additional interpretation. You can discuss these further with your clinical team.

We understand that these results can be complex.  If at any point you would like to help you sort through the information on our report, please feel free to request a phone call from one of our genetic counselors.

Copy of Sample PGT Result Summary Table

Embryo #NGS Results (ngs)DiagnosisEmbryo TransferComments
346, XY / ngs(1-22)x2,(XY)x1EUPLOID MaleYES
446, XX / ngs(1-22,X)x2EUPLOID FemaleYES
5FAInconclusiveNORe-biopsy recommended
6MOS 47, XY, +16 / 46, XYMOSAIC 30%See further interpretation
7Complex Chromosomal AbnormalitiesANEUPLOIDNO
846, XY, del(4)(p12p16.3)ANEUPLOIDNOdel(4) – 44 Mb


Aneuploid (abnormal):  an abnormal number of chromosomes was detected.

Complex Chromosomal Abnormalities: a complex abnormal results indicates there several abnormal findings.

Deletion: a missing piece of a chromosome, rather than an entire missing chromosome. The report will show ‘del’ followed by the chromosome segment that was found to be absent. 

Duplication: an extra piece of a chromosome, rather than an entire extra chromosome. The report will show ‘dup’ followed by the chromosome segment that was duplicated. 

Euploid (normal): a normal number of chromosomes (46) was detected.

Failed Amplification (FA): DNA within the sample may be degraded or may not yield a result.

Inconclusive: The interpretation indicates that a reliable result cannot be achieved with the sample submitted. This could be due to the lack of DNA (limited material or absence of sample) or poor data quality (no intact nucleus, poor embryo quality, degraded DNA). A re-biopsy is recommended if testing is still desired.

Monosomy: one chromosome of a normal pair is absent. The report will show a “-” before the missing chromosome.

Mosaic (MOS): this result indicating that cells within the same biopsy have a mixed chromosome makeup. It can involve either whole chromosome or partial chromosomes segment(s). The report will note the normal and the abnormal cell lines, and show “mos” before the abnormal cell line result. Indicating that the reported changes are mosaic.

Segmental deletion/duplication (segmental aneuploidy): a partial deletion (del) or duplication (dup) indicates that a piece of a chromosome is missing or extra.  

Trisomy: The presence of an extra copy of a chromosome was detected. The report will show a “+” before the extra chromosome.


1Franasiak JM, Forman EJ, Hong KH, Werner MD, Upham KM, Treff NR, Scott RT Jr. The nature of aneuploidy with increasing age of the female partner: a review of 15,169 consecutive trophectoderm biopsies evaluated with comprehensive chromosomal screening. Fertil Steril. 2014 Mar;101(3):656-663.e1. doi: 10.1016/j.fertnstert.2013.11.004. Epub 2013 Dec 17. PMID: 24355045.

2 RGI Internal data

3Viotti M, Victor AR, Barnes FL, Zouves CG, Besser AG, Grifo JA, Cheng EH, Lee MS, Horcajadas JA, Corti L, Fiorentino F, Spinella F, Minasi MG, Greco E, Munné S. Using outcome data from one thousand mosaic embryo transfers to formulate an embryo ranking system for clinical use. Fertil Steril. 2021 May;115(5):1212-1224. doi: 10.1016/j.fertnstert.2020.11.041. Epub 2021 Mar 6. PMID: 33685629.

By Agnes Machaj, Genetic Counseling Manager, RGI