PGT Testing Abroad: Chromosomal Screening Explained

Bottom line: PGT (preimplantation genetic testing) screens embryos for chromosomal abnormalities before transfer, improving per-transfer success rates and reducing miscarriage risk. In the US, PGT adds $3,000–$6,000 to an IVF cycle. In Colombia, the same NGS-based testing costs $1,000–$2,500. The technology is identical — next-generation sequencing performed on a trophectoderm biopsy at the blastocyst stage.

Types of Preimplantation Genetic Testing

PGT-A (Aneuploidy Screening)

The most common type. PGT-A screens all 23 pairs of chromosomes for numerical abnormalities — extra or missing chromosomes (aneuploidy). Aneuploid embryos are the leading cause of IVF failure and early miscarriage. By selecting euploid (chromosomally normal) embryos for transfer, PGT-A can:

Increase per-transfer pregnancy rates (55–65% for PGT-A tested embryos vs. 40–50% untested)
Reduce miscarriage rates (approximately 10–15% after PGT-A vs. 20–25% without)
Support single embryo transfer (SET), reducing multiple pregnancy risk

PGT-M (Monogenic/Single Gene Disorders)

Tests for specific inherited genetic conditions when one or both partners are known carriers. Examples include cystic fibrosis, sickle cell disease, Tay-Sachs disease, BRCA1/BRCA2 mutations, Huntington's disease, and muscular dystrophy. PGT-M requires a custom probe designed for your specific mutation — this takes 2–4 weeks to develop before the IVF cycle begins.

PGT-SR (Structural Rearrangements)

For patients with known chromosomal translocations or inversions — structural differences in how chromosomes are arranged. These patients are at higher risk of producing unbalanced embryos, leading to recurrent miscarriage or failed implantation.

What PGT does NOT do

PGT-A and PGT-M are diagnostic tools scoped to chromosomal abnormality detection and specific genetic disease screening. They identify embryos affected by conditions like Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), or single-gene disorders. This testing is a medical screening tool — not a selection mechanism for non-medical traits.

How the Testing Process Works

IVF cycle: Standard stimulation, retrieval, and fertilization.
Embryo culture to blastocyst: Embryos are grown for 5–7 days to the blastocyst stage.
Biopsy: An embryologist removes 5–10 cells from the trophectoderm (outer cell layer that becomes the placenta). The inner cell mass (which becomes the baby) is not touched.
Vitrification: Embryos are frozen while biopsy samples are sent to the genetics lab.
NGS analysis: Next-generation sequencing analyzes all 23 chromosome pairs. Results typically return in 7–14 days.
Frozen embryo transfer: A euploid embryo is thawed and transferred in a subsequent cycle (usually the following month).

Cost Comparison

Component	US Cost	Colombia Cost
PGT-A (up to 8 embryos)	$3,000–$6,000	$1,000–$2,500
PGT-M (custom probe + testing)	$4,000–$8,000	$1,500–$3,500
PGT-SR	$3,500–$6,000	$1,200–$3,000
Additional embryos (per embryo)	$200–$400 each	$100–$200 each

Same technology, different price

Colombian fertility labs use the same Illumina or Thermo Fisher NGS platforms as leading US genetics laboratories. The biopsy technique, sequencing methodology, and interpretation criteria are standardized globally. What differs is the cost structure — not the science.

Who Benefits Most from PGT-A?

PGT-A is most valuable for:

Women over 35: Aneuploidy rates increase significantly with maternal age. At 35, approximately 30–40% of embryos are aneuploid. By 40, that rises to 60–75%.
Patients with recurrent miscarriage: Chromosomal abnormalities cause 50–60% of first-trimester miscarriages.
Patients with prior failed transfers: If morphologically good embryos failed to implant, aneuploidy may have been the reason.
Patients producing many embryos: When you have 6+ blastocysts, PGT-A helps prioritize which to transfer first.

When PGT-A may not be necessary

For younger patients (under 35) with their first IVF cycle who produce a small number of embryos (1–3), the benefit of PGT-A is debated. Testing reduces the number of transferable embryos (some normal embryos may receive inconclusive results), and younger patients already have lower aneuploidy rates. Discuss with your specialist whether testing is appropriate for your specific situation.

PGT-A and the freeze-all approach

PGT-A requires embryos to be frozen while results are processed (7–14 days). This means a "freeze-all" approach — no fresh transfer. Current evidence shows that frozen embryo transfers have comparable or slightly higher success rates than fresh transfers in most cases, so this isn't a disadvantage. It also allows endometrial preparation to be optimized independently.

Is PGT Right for You?

A specialist can assess whether genetic testing would benefit your specific situation — and provide transparent pricing for the complete cycle including PGT.

Request a Free Consultation →