What is Preimplantation Genetic Testing (PGT)? Differences Between PGT-A, PGT-M, and PGT-SR

Preimplantation Genetic Testing (PGT) is a testing technique performed during in vitro fertilization (IVF) cycles, where a small number of cells are removed from the embryo for chromosomal or genetic analysis before transfer into the uterus. Based on the purpose of testing, it is divided into three types: PGT-A (chromosomal aneuploidy), PGT-M (monogenic/single-gene disorders), and PGT-SR (chromosomal structural rearrangements). PGT is an optional, self-paid procedure and is not a mandatory part of IVF. Whether it is suitable must be evaluated and explained by a reproductive medicine specialist based on individual circumstances. The following is a neutral educational summary, not medical advice. Actual indications and regulations are subject to physician explanation and official announcements from competent authorities.

National Laws and Regulations Database - 《Assisted Reproduction Act》 ↗

PGT-A, PGT-M, PGT-SR: Purposes and Indications of the Three Tests

PGT is divided into three types based on testing purpose, with different names, uses, and indications:

Type	Testing Purpose	Commonly Discussed Candidates (evaluated by physician)
PGT-A (Chromosomal Aneuploidy)	Analyzes whether the embryo has the normal number of chromosomes	Advanced maternal age, recurrent miscarriage, repeated implantation failure, etc.
PGT-M (Monogenic Disorders)	Tests for known single-gene genetic disorders	One or both partners are carriers of a specific genetic disease
PGT-SR (Chromosomal Structural Rearrangements)	Detects abnormalities related to chromosomal structural rearrangements	One partner carries a chromosomal structural rearrangement such as balanced translocation

The three tests have different purposes and cannot replace each other. Whether they are applicable and which one to choose must be evaluated by a reproductive medicine specialist based on individual circumstances. This section is a neutral educational summary, not medical advice.

PGT Testing Process: From Egg Retrieval, Biopsy to Frozen Embryo Transfer

PGT is performed during an IVF cycle. The general process is as follows (actual steps vary by clinic and individual condition):

Ovarian stimulation and egg retrieval: Same as standard IVF; eggs are retrieved and fertilized in vitro.
Embryo culture to blastocyst stage: Embryos are cultured to the blastocyst stage (day 5–6).
Embryo biopsy: An embryologist removes a few trophectoderm cells (which will form the placenta) for testing.
Embryo freezing: After biopsy, embryos are usually frozen and stored while awaiting test results.
Result interpretation and subsequent transfer: After results are available, the physician explains them, and a suitable embryo is thawed and transferred in a later cycle.

Because embryos are typically frozen first and transferred after results, PGT cycles often follow a "frozen embryo transfer" schedule, which differs from fresh transfer. Biopsy is an invasive procedure with certain risks, performed by the laboratory according to protocols. For more information, please refer to the "Frozen Embryo Transfer" and "IVF Cycle" pages on this site.

Should You Undergo PGT? Neutral Aspects to Discuss with Your Physician

PGT is an additional, self-paid, non-essential testing option. Whether to proceed is an individual medical decision. The following neutral aspects can be discussed with your physician:

Clear purpose: Whether you want to know about chromosomal number (PGT-A), known monogenic disorders (PGT-M), or chromosomal structural rearrangements (PGT-SR).
Test limitations: Results may show mosaicism or have interpretation limitations; they are not absolute and do not cover all diseases or risks.
Cost and timeline: Testing fees are separate from IVF cycle costs; current government subsidies do not cover PGT. Additionally, frozen transfer is usually required, extending the timeline.
Number of embryos available for testing: The number of embryos that can be biopsied affects the significance of testing; this must be evaluated by the physician.

First step today (immediate action): Write down your questions in one sentence—for example, "Given my age and condition, which type of PGT (PGT-A/PGT-M/PGT-SR) is suitable for me? What are the costs and timeline?"—and ask your reproductive medicine specialist directly at your next visit, requesting a detailed fee breakdown. Whether to test and how to interpret results should be based on the physician's explanation tailored to your individual condition. This page provides neutral educational information, not medical advice.

FAQ

What is PGT? How is it different from standard IVF?

PGT is a technique performed during an IVF cycle where a small number of cells are removed from the embryo (usually at the blastocyst stage) for chromosomal or genetic analysis before transfer. Standard IVF does not necessarily include PGT; adding it is an optional self-paid service that must be evaluated by a physician based on individual circumstances. This page provides neutral information, not medical advice.

What is the difference between PGT-A, PGT-M, and PGT-SR?

PGT-A tests whether the embryo has the normal number of chromosomes (aneuploidy); PGT-M tests for known single-gene genetic disorders; PGT-SR is used when one partner carries a chromosomal structural rearrangement (e.g., balanced translocation). The three tests have different purposes, and the appropriate test is determined by the physician.

In what situations might a physician discuss PGT?

Common discussion scenarios include advanced maternal age, recurrent miscarriage, repeated implantation failure in IVF, or known genetic disorders or chromosomal abnormalities in the family or couple. These are "discussion indications" and not universally applicable; the decision to proceed is made jointly by the physician and the couple.

How is PGT performed? Does it harm the embryo?

PGT is usually performed when the embryo reaches the blastocyst stage. An embryologist removes a few trophectoderm cells (which will form the placenta) for testing. The embryo is typically frozen first, and after results are available, it is thawed and transferred in a later cycle. Biopsy is an invasive procedure with certain risks, performed by the laboratory and physician according to protocols, and explained to the patient.

How much does PGT cost? Is it subsidized?

PGT is a self-paid service. Costs vary by test type, number of embryos tested, and clinic, and are separate from IVF cycle fees. Current government IVF subsidies do not cover PGT costs. For actual pricing and applicability, please request a detailed breakdown from your clinic. This page provides neutral information.

Are PGT results always accurate?

PGT analyzes a small number of cells and may show mosaicism (inconsistent results among cells of the same embryo) or have interpretation limitations; it is not absolute. Result interpretation and subsequent management must be determined by the physician based on the overall situation. Test results do not equate to a definitive outcome for pregnancy or fetal health.

Are there regulations governing PGT in Taiwan?

Assisted reproduction in Taiwan is regulated by the "Artificial Reproduction Act." Facilities must be licensed by the Ministry of Health and Welfare. Procedures involving genetic testing and embryo handling must comply with relevant regulations and institutional protocols. For reference, this site compiles information on licensed facilities based on the Ministry's list.

Does undergoing PGT guarantee no miscarriage or abnormal baby?

No. PGT is an auxiliary testing tool that provides information about embryo chromosomes or specific genes. It cannot exclude all risks or cover all diseases. Routine prenatal care is still necessary during pregnancy. Whether to undergo PGT and how to interpret results are individual medical decisions made by the physician and the couple. This page provides neutral educational information, not medical advice.

Further References (Official Data Sources)

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Updated: 2026-07-29 · This page is a neutral compilation of information, for reference only, not medical advice, and does not constitute any treatment commitment. Actual regulations and treatments should be based on announcements from competent authorities and explanations from qualified physicians.