PGT-A, PGT-M and PGT-SR Compared: Which Test Is Being Discussed for Your Case in Thailand?

PGT-A, PGT-M and PGT-SR are three types of preimplantation genetic testing. They differ mainly in what they are designed to look for. PGT-A looks at the number of chromosomes in an embryo. PGT-M looks for a specific inherited condition that runs in a family. PGT-SR looks at chromosome rearrangements, such as a balanced translocation, that a parent may carry. None of them is a general “best” test, and none guarantees a pregnancy or a healthy child. Which one is relevant, if any, depends on your medical history, your family history and what your treating clinician recommends.

At a glance

• PGT-A — screens for extra or missing chromosomes (aneuploidy) across the embryo’s chromosome set.
• PGT-M — tests for a known single-gene (monogenic) condition that a family carries.
• PGT-SR — tests for chromosome structural rearrangements, such as translocations or inversions.
• All three require an IVF cycle and a biopsy of embryo cells, usually at the blastocyst stage.
• The right test — or no test — is a clinical decision based on your individual situation, not a menu choice.

What each test is actually looking at

It helps to separate the three tests by the question each one tries to answer.

PGT-A: chromosome number

PGT-A stands for preimplantation genetic testing for aneuploidy. Aneuploidy means an embryo has an extra or missing chromosome. Human embryos commonly have chromosome errors, and the likelihood tends to rise with maternal age, though it can occur at any age. PGT-A is designed to estimate whether an embryo has the expected number of chromosomes. It is a screening test, not a diagnosis of a specific disease, and it does not read the DNA sequence of individual genes.

PGT-M: a known single-gene condition

PGT-M stands for preimplantation genetic testing for monogenic disorders. It is used when a family is known to carry a specific inherited condition caused by a change in a single gene — for example, certain inherited blood disorders, cystic fibrosis or other conditions a clinician has identified. PGT-M usually requires prior information about the exact gene change in the family, often confirmed through a blood or saliva sample from one or both parents. Without that information, the laboratory may not be able to build a reliable test.

PGT-SR: chromosome rearrangements

PGT-SR stands for preimplantation genetic testing for structural rearrangements. It is relevant when a parent carries a chromosome rearrangement such as a balanced translocation or an inversion. People with a balanced rearrangement are often healthy themselves, but they may have a higher chance of producing embryos with unbalanced chromosome material. PGT-SR is designed to identify those unbalanced embryos. Like PGT-M, it usually depends on knowing the specific rearrangement in advance.

Side-by-side comparison

Feature	PGT-A	PGT-M	PGT-SR
Main purpose	Screen for extra or missing chromosomes	Test for a known single-gene condition	Test for a known chromosome rearrangement
Typical reason it is discussed	Age-related chromosome risk, recurrent implantation failure or recurrent pregnancy loss, at a clinician’s discretion	Family history of a specific inherited condition	Parent carries a balanced translocation or similar rearrangement
Information needed beforehand	None specific to a gene	Details of the family’s gene change	Details of the parent’s rearrangement
What it does not do	Does not test for single-gene diseases	Does not screen the whole chromosome set	Does not test for single-gene diseases
Result type	Screening estimate	Targeted result for that condition	Targeted result for that rearrangement

This table is a general orientation only. Real clinical use is more nuanced, and some patients may be offered more than one type of testing, or none.

Why the right test depends on your history

There is no single test that fits everyone. The choice — or the decision not to test — usually follows from a few questions:

• Is there a known inherited condition in the family? If yes, PGT-M may be discussed, and the specific gene change usually needs to be confirmed first.
• Does either parent carry a chromosome rearrangement? If yes, PGT-SR may be relevant.
• Is there a history of recurrent pregnancy loss or repeated unsuccessful transfers? A clinician may discuss PGT-A, though evidence and guidelines vary and it is not automatically recommended for everyone.
• What is the maternal age and overall fertility picture? These factors can influence how a clinician frames the possible benefits and limits of PGT-A.
• What does the embryology laboratory offer? Not every clinic performs every type of PGT, and referral patterns differ.

Because these factors interact, the same acronym can mean different things in different consultations. A test that is reasonable for one patient may be unnecessary or unsuitable for another.

What PGT results can and cannot tell you

PGT is a laboratory test performed on a small number of cells taken from an embryo. It provides information about those cells, which is used to estimate the status of the embryo. It does not guarantee that an embryo will implant, that a pregnancy will continue, or that a child will be free of all health conditions. It also does not replace prenatal testing or newborn screening, and it cannot detect every possible genetic or chromosomal issue.

Results are usually reported in categories such as “euploid” (expected chromosome number), “aneuploid” (extra or missing chromosomes), “mosaic” (a mix of cells with different chromosome numbers) or “inconclusive.” How a clinic interprets and acts on these categories can vary, and some results require genetic counselling to understand.

Alternatives and limitations to keep in mind

PGT is one option among several. Depending on your situation, alternatives or additions may include:

• Proceeding with IVF without PGT and using ultrasound or other standard monitoring.
• Using donor gametes, if medically indicated and consistent with your values and local rules.
• Prenatal screening or diagnostic testing during pregnancy, such as ultrasound, cell-free DNA screening, chorionic villus sampling or amniocentesis.
• Genetic counselling before or after testing to interpret results and discuss implications.

Limitations include the possibility of inconclusive results, the small but real chance of a result that does not reflect the whole embryo, and the fact that PGT adds cost and complexity to an IVF cycle. It is not a required step for all patients, and it is not a guarantee of success.

Questions to ask a clinic in Thailand

If you are considering PGT in Thailand, these questions can help you compare what different clinics actually offer and how they work:

1. Based on my history, which type of PGT — if any — would you discuss with me, and why?
2. What information or samples do you need from me before testing can be arranged?
3. Which laboratory performs the testing, and how are results reported back to me?
4. How do you explain mosaic, inconclusive or borderline results, and what are the options afterward?
5. What are the costs involved, and what is included or excluded?
6. What are the timelines — from consultation to biopsy to result — and how might they affect my treatment plan?
7. What are the legal or regulatory considerations for PGT in Thailand that I should be aware of?
8. Do you provide genetic counselling, and is it included or separate?

Next-step checklist

• Gather your personal and family medical history, including any known genetic conditions or chromosome findings.
• Ask your current clinician whether any prior genetic test results can be shared with a clinic in Thailand.
• Request a consultation that specifically discusses PGT options and limitations, not just IVF in general.
• Ask for written information about costs, timelines and what happens if results are inconclusive.
• Consider speaking with a genetic counsellor before deciding, especially if PGT-M or PGT-SR is being discussed.
• Confirm any visa, travel or documentation requirements directly with the clinic and relevant authorities, as these can change.

For more background, see our PGT in Thailand overview and browse the guides section. If you have a specific question, the FAQ may help.

Frequently asked questions

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

PGT-A screens for extra or missing chromosomes across the embryo's chromosome set. PGT-M tests for a specific single-gene condition that a family is known to carry. PGT-SR tests for a known chromosome rearrangement, such as a balanced translocation. They answer different questions and are not interchangeable.

Can I choose which PGT test I want?

The choice is usually a clinical decision based on your medical and family history, not a simple preference. A clinician can explain which test, if any, is relevant for your situation, and why. Some patients may be offered more than one type of testing, or none.

Does PGT guarantee a healthy baby?

No. PGT provides information about a small sample of cells from an embryo. It cannot guarantee implantation, an ongoing pregnancy, or that a child will be free of all health conditions. It also does not replace prenatal testing or newborn screening.

What should I ask a clinic in Thailand about PGT?

Useful questions include which type of PGT is being discussed and why, what information the clinic needs from you, which laboratory performs the testing, how results are reported, what costs are involved, and what the timelines are. It is also reasonable to ask about genetic counselling and any legal or regulatory considerations.

Is PGT required for everyone doing IVF?

No. PGT is an optional add-on to IVF that is discussed in specific situations. Many patients proceed with IVF without PGT. Whether it is appropriate for you depends on your individual history and your clinician's assessment.

Continue your research

• PGT in Thailand overview
• PGT and IVF guides
• Frequently asked questions

Medical information notice: This article is educational and does not replace individual assessment, diagnosis, genetic counselling or treatment advice from a licensed clinician. Provider services, availability, fees and policies should be verified directly before booking.