At a glance
A plain-English guide to the three main preimplantation genetic testing types, what each looks for, who they may be relevant for, and what to ask a Thai clinic.
PGT-A, PGT-M and PGT-SR are three different types of preimplantation genetic testing used during IVF. They are not interchangeable. 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 structure, usually when a parent has a known rearrangement. In Thailand, as elsewhere, the right test — if any — depends on your medical history, your family history and what your clinic can actually offer. This guide explains the differences in plain English and lists questions to ask before you decide.
At a glance
- PGT-A — checks chromosome number (for example, extra or missing chromosomes).
- PGT-M — checks for a specific gene change linked to a known inherited condition.
- PGT-SR — checks for chromosome structural rearrangements, such as translocations.
- None of these tests is a guarantee of pregnancy, live birth or a healthy child.
- Not every patient needs PGT. Some clinics may recommend it; others may not.
- Availability, eligibility and cost vary by clinic and should be confirmed directly.
What is preimplantation genetic testing?
Preimplantation genetic testing (PGT) is a group of laboratory tests performed on a small number of cells taken from an embryo during IVF, usually before the embryo is transferred to the uterus or frozen. The goal is to give the care team more information about the embryo’s chromosomes or genes.
PGT is not a treatment for infertility. It is a screening or diagnostic tool that may help some patients make decisions about which embryo(s) to transfer. It does not improve the quality of an embryo, and it cannot guarantee that an embryo will implant, that a pregnancy will continue, or that a child will be free of all health conditions.
The three main PGT types
PGT-A: chromosome number
PGT-A stands for preimplantation genetic testing for aneuploidy. Aneuploidy means an embryo has an abnormal number of chromosomes — for example, an extra copy or a missing copy of a particular chromosome. PGT-A is sometimes called chromosome screening.
PGT-A does not look for a specific inherited disease. It gives a broad view of chromosome number across the embryo’s cells. It may be discussed with patients who are older, who have had repeated implantation failure or recurrent pregnancy loss, or who have had previous IVF cycles. However, professional guidelines differ on who should be offered PGT-A, and it is not universally recommended. Some embryos with abnormal PGT-A results can still develop, and some with normal results do not implant. This is why PGT-A is best understood as one piece of information, not a final answer.
PGT-M: a specific inherited condition
PGT-M stands for preimplantation genetic testing for monogenic (single-gene) disorders. It is used when a family has a known inherited condition caused by a change in a single gene — for example, cystic fibrosis, spinal muscular atrophy, or certain types of thalassemia. PGT-M requires that the specific gene change in the family has already been identified, usually through genetic testing of the parents or an affected family member.
PGT-M is highly targeted. It looks only for the condition in question, not for other chromosome problems. It is typically considered when both parents are carriers of the same recessive condition, when one parent has a dominant condition, or when there is a known X-linked condition in the family. A genetic counsellor or specialist usually needs to be involved before PGT-M can be arranged.
PGT-SR: chromosome structure
PGT-SR stands for preimplantation genetic testing for structural rearrangements. It is used when one parent has a known chromosome rearrangement, such as a translocation, inversion or deletion. These rearrangements can increase the risk of miscarriage or of a child being born with a chromosome condition.
PGT-SR is different from PGT-A because it looks at the structure and arrangement of chromosomes, not just the number. Like PGT-M, it requires prior genetic testing to characterise the rearrangement. It is not a general screening test and is not appropriate for everyone.
How the three tests compare
| Feature | PGT-A | PGT-M | PGT-SR |
|---|---|---|---|
| What it looks for | Chromosome number (aneuploidy) | A specific single-gene condition | Chromosome structural rearrangements |
| Typical reason to consider | Age, repeated implantation failure, recurrent loss, or clinic policy | Known inherited condition in the family | Known translocation or other rearrangement in a parent |
| Prior genetic testing needed? | No | Yes — the specific gene change must be identified | Yes — the rearrangement must be characterised |
| Scope | Broad chromosome screen | Targeted to one condition | Targeted to a structural issue |
| Guarantee of outcome? | No | No | No |
This table is a general orientation only. Your clinic will explain which test, if any, is relevant to your situation.
Who might be offered each test?
PGT is not a routine part of every IVF cycle. The following are common reasons a clinic might discuss a particular test, but they are not rules and they are not recommendations.
- PGT-A may be discussed for patients with advanced maternal age, a history of recurrent miscarriage, repeated IVF failure, or a previous pregnancy with a chromosome condition. Some clinics offer it more broadly; others do not.
- PGT-M may be discussed when there is a known single-gene disorder in the family and the specific mutation has been identified. It usually requires genetic counselling and a custom laboratory setup.
- PGT-SR may be discussed when a parent carries a balanced translocation or another structural rearrangement, which can affect the chance of a healthy pregnancy.
In all cases, the decision is individual. A clinic may recommend for or against PGT based on your medical history, the number of embryos available, laboratory capacity and other factors.
What PGT can and cannot tell you
PGT can provide information about the chromosomes or genes of the cells that were tested. It cannot tell you whether an embryo will implant, whether a pregnancy will be healthy, or what the child’s future health will be. It also cannot detect every possible genetic condition. Some tests have technical limitations, and occasionally results are inconclusive or need to be repeated.
It is also important to know that PGT is not a substitute for prenatal testing. Some patients choose to have prenatal testing during pregnancy even after PGT, because PGT is not 100% accurate and because some conditions cannot be detected in an embryo.
Alternatives to PGT
Depending on your situation, alternatives may include:
- Proceeding with IVF without PGT and transferring an embryo based on standard selection.
- Using donor eggs or donor sperm, which may change the genetic risk profile.
- Prenatal testing (such as chorionic villus sampling or amniocentesis) during pregnancy, if you become pregnant.
- Preconception genetic carrier screening for both partners, which can identify risks before treatment.
- Choosing not to pursue IVF or genetic testing at all, and instead exploring other family-building options.
These are not necessarily better or worse than PGT; they are different paths with different trade-offs. A genetic counsellor or your treating doctor can help you weigh them.
Questions to ask a clinic in Thailand
If you are considering PGT in Thailand, the following questions can help you understand what is available and what to expect. Ask for written information where possible.
- Which PGT tests does your laboratory perform, and are they done on-site or sent to another facility?
- For my situation, which test — if any — would you recommend, and why?
- What are the limitations of the test you are recommending?
- What proportion of embryos typically receive a result, and what happens if the result is inconclusive?
- What are the costs of the test itself, and are there separate costs for genetic counselling, embryo biopsy, freezing or storage?
- Do you require genetic counselling before PGT-M or PGT-SR, and can you provide it or refer me?
- How will the results affect the decision about which embryo to transfer?
- What are the laws or clinic policies in Thailand that apply to PGT and to my situation?
- What support is available for international patients, such as interpretation or help with travel logistics?
- Can you provide information in writing so I can review it with my home doctor?
Next steps for international patients
If you are new to PGT, a practical first step is to gather your own medical and family history, including any previous genetic test results. Then contact a few clinics that accept international patients and ask the questions above. Compare their answers, not just their prices. You may also want to speak with a genetic counsellor in your home country before you travel, so you understand the test and its implications.
For more general information about PGT in Thailand, see our PGT in Thailand guide. If you are planning a trip for treatment, our international patients page covers practical topics. You can also browse our guides and FAQ for related questions.
A note on uncertainty
PGT is a rapidly evolving field. Guidelines, laboratory techniques and clinic policies can change. This article is for general education and does not replace personalised medical advice. Always confirm details directly with your treating clinic and, where relevant, with a qualified genetic counsellor.
Frequently asked questions
What is the main difference between PGT-A, PGT-M and PGT-SR?
PGT-A looks at the number of chromosomes in an embryo. PGT-M looks for a specific inherited condition caused by a single gene change. PGT-SR looks at the structure of chromosomes, usually when a parent has a known rearrangement such as a translocation. They are different tests used for different reasons.
Do I need PGT for IVF in Thailand?
Not necessarily. PGT is not required for every IVF cycle. Whether it is offered or recommended depends on your medical history, family history, the clinic's policy and other factors. Your treating doctor can explain if it is relevant for you.
Can PGT guarantee a healthy baby?
No. PGT can provide information about the chromosomes or genes of the tested embryo, but it cannot guarantee pregnancy, live birth or a child free of all health conditions. It also cannot detect every possible genetic issue. Some patients still choose prenatal testing during pregnancy.
How much does PGT cost in Thailand?
Costs vary widely depending on the clinic, the type of test, the number of embryos tested and whether genetic counselling or other services are included. We do not list prices because they change and depend on your individual situation. Ask each clinic for a written cost breakdown.
What should I ask a Thai clinic before choosing PGT?
Ask which tests they perform, whether the laboratory is on-site, what the limitations are, how results are reported, what the total cost includes, whether genetic counselling is required, and how results will affect embryo transfer decisions. Also ask about support for international patients.
Continue your research
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.
Need help turning research into a shortlist?
