PGT Results & Testing Limitations

Preimplantation genetic testing reads a few cells taken from an embryo, not the whole embryo, so every result carries some uncertainty. A transfer of a “normal” embryo can still end in miscarriage, and an embryo labeled abnormal may not have been. Neither outcome, on its own, shows that anyone was careless. A PGT lawsuit usually turns on narrower questions: was a sample mishandled, was the wrong result reported, or were you told the test could do more than it can?

What PGT-A, PGT-M and PGT-SR can and cannot tell you

PGT is a group of tests run on embryos created through IVF, before an embryo is transferred to the uterus. The three main types answer different questions1:

• *PGT-A (aneuploidy)* screens for missing or extra chromosomes across all 22 pairs, plus the X and Y chromosomes1.
• *PGT-M (monogenic)* is targeted to a single-gene disorder, usually one a parent is known to carry1.
• *PGT-SR (structural rearrangements)* is used when a parent has a chromosome rearrangement, such as a translocation, inversion, deletion or insertion, that can leave embryos with missing or extra chromosome material1.

Each test answers only its own question. PGT-M targets one gene condition and is not a chromosome screen unless PGT-A is run as well. ACOG says prenatal testing is especially important after PGT-M or PGT-SR when PGT-A was not also done1. ACOG also lists limits shared across PGT: trouble detecting very small deletions or duplications, new (de novo) gene changes and imprinting disorders1.

No PGT result promises a pregnancy or a healthy baby. ACOG says false-positive and false-negative results are possible with every type of PGT, and that a normal result is not a guarantee of a newborn without genetic abnormalities1. Pregnancy is not assured either. In a 2026 study of 9,828 single-embryo transfers, about 60% of transfers of embryos reported as euploid (chromosomally normal) ended in a live birth6. For PGT-A in particular, ASRM and SART wrote in 2024 that its value as a routine screening test for every IVF patient has not been shown, and that recent multicenter trials in patients with blastocysts available found overall pregnancy outcomes similar with or without it2.

Sampling, mosaicism and residual risk, test by test

Every type of PGT starts with a biopsy of a few cells. That small amount of DNA is the source of most built-in uncertainty, and the details differ by test.

PGT-A: accuracy and mosaic results

A 2025 review pooled 109 studies. When biopsy results were checked against the rest of the embryo, an “aneuploid” call held up about 89% of the time and a “euploid” call about 94% of the time. After transfer of a euploid embryo, the pooled misdiagnosis rate was 0.2%. Results labeled mosaic were much less reliable: only about 53% were confirmed as mosaic or aneuploid3.

Mosaicism means the biopsy showed a mix of normal and abnormal cells, or an in-between reading. What that means for the embryo is still debated. In the 2026 study, embryos with mosaic-range readings had a somewhat lower live birth rate than euploid embryos (53.2% vs. 60.0%). The authors, who work with a testing lab and a clinic network, concluded that in their setting, reporting mosaicism gave no clinical benefit and should not guide routine embryo selection6. A 2026 comparison of 11 professional societies found their advice on mosaic embryos is not uniform7.

PGT-M: allele drop-out and recombination

PGT-M looks for a known gene change using very little DNA. ESHRE’s technical guidance names the risks that come with that: the DNA may fail to amplify, outside DNA can contaminate the sample, and one copy of the gene can “drop out” and go undetected. A recombination near the gene that is not detected can also cause a misdiagnosis4. ESHRE expects the lab to report the test’s limits and the residual risk, meaning the chance that a result is still wrong4.

PGT-SR: what the method can see

PGT-SR looks for unbalanced pieces of chromosomes. Some common methods cannot tell an embryo with typical chromosomes from one that carries the same balanced rearrangement as the parent, though haplotype-based methods can5. Very small segments, or breaks near the ends of chromosomes, may be missed, and mosaicism can lead to a misread5.

Across all three tests, a report may use labels like these:

• *Euploid or normal*: no imbalance found in what was tested
• *Aneuploid or abnormal*: missing or extra chromosome material found
• *Mosaic or intermediate*: a mixed or in-between reading
• *Affected, unaffected or carrier*: PGT-M status for the family’s gene
• *Balanced or unbalanced*: PGT-SR status, if the method can tell
• *Inconclusive or no result*: no readable answer, a known risk ESHRE lists5

Testing limitation or preventable error?

This is the question at the center of any claim review. A result can be wrong for reasons no one could control. It can also be wrong because of a step someone should have done differently. The same bad outcome can come from either.

Facts that often call for a closer look include:

• Genetic results that do not match a later prenatal test, the child, or the embryo’s own retest, especially if more than one embryo is involved. See embryo genetic testing sample mix-ups.
• Embryos discarded after a mosaic, abnormal or inconclusive result without counseling on what that label could mean. See embryos discarded after genetic testing.
• A “normal” result offered as reassurance about something the test was never designed to check.
• A warning, limit or residual-risk figure on the lab report that was never passed on to you.
• Consent forms, brochures or websites that described the test in terms the published evidence does not support.

Test-specific problems are covered in more depth on our pages about PGT-A testing errors, PGT-M testing errors and PGT-SR testing errors.

Genetic counseling, informed consent and confirmatory testing

PGT is complex, and the guidance puts weight on what patients are told before testing and after results come back. Good counseling covers what the test does not check, what a mosaic or inconclusive result could mean, and what choices remain. It also covers testing during pregnancy. Diagnostic tests such as chorionic villus sampling (CVS), usually done at 10 to 13 weeks, and amniocentesis, usually done at 15 to 20 weeks, test cells from the placenta or fetus14.

What professional guidance says

ACOG (2020, reaffirmed 2025)

Prenatal screening or diagnostic testing should be offered to everyone who had PGT-A, and it is especially important after PGT-M or PGT-SR done without PGT-A1.

ASRM and SART (2024)

The value of PGT-A as a routine screening test for all IVF patients has not been demonstrated2.

ESHRE (2020)

Records should include a counseling report on the test’s benefits and limits, and informed consent that includes a risk assessment and the test’s limitations5.

ESHRE PGT-M (2020)

Achieving a pregnancy and prenatal diagnosis should be considered in all cases before a PGT-M cycle begins4.

Society comparison (2026)

There is no uniform guidance on prenatal testing after PGT-A7.

A gap in counseling is not automatically a legal claim. But when a family made a lasting choice, such as discarding embryos or skipping prenatal testing, based on an incomplete or inaccurate explanation, that gap can matter.

Where PGT lawsuits stand in October 2026

Recent class actions over PGT-A focus on how the test was marketed, not on lab mix-ups. These suits against several PGT-A labs claim the companies misrepresented what the test can do; a March 2026 news report put the number of people in those cases at about 3,0008. Only one company, Natera, answered the outlet’s request for comment; it said the litigation against it is without merit8. Courts have ruled differently at the early stages:

Selected PGT-A marketing cases

1. August 4, 2025

   A federal court in California granted Natera’s motion to dismiss a proposed class action over its PGT-A advertising, finding the claims were not pleaded with enough detail, and allowed the plaintiffs to amend9.

2. March 2026

   Bay News 9 reported class actions against labs including CooperSurgical/CooperGenomics, Natera, Progenesis and Igenomix, alleging the test’s limits were not made clear8.

3. September 17, 2026

   A federal court in San Diego denied Progenesis’s motion to dismiss an amended class complaint, so the case continues10.

4. October 8, 2026

   A federal court in New Jersey dismissed a class action against Genomic Prediction because the plaintiffs had not alleged an injury-in-fact. The court noted that each plaintiff’s result listed 98.6% accuracy, within the 98% to 99% their consent forms allegedly stated. The plaintiffs may amend11.

These are early rulings on whether a complaint can go forward. None is a finding that a lab did or did not do anything wrong, and the outcome of each case remains open as of October 2026.

CBW Law separates what PGT cannot do from what someone failed to do, and only the second can support a claim.

How an unexpected PGT result can affect a family

A wrong or misunderstood result can change a family’s path in ways that are hard to undo:

• Embryos discarded or left in storage because they were labeled abnormal
• More retrievals and transfers, with the cost, medication and physical strain each one brings
• Pregnancy loss after the transfer of an embryo reported as normal
• A child born with a condition the testing was meant to look for
• Grief, guilt and doubt about decisions made in good faith
• Hard choices about remaining embryos when trust in the results is gone

When to talk to a lawyer about a PGT result

It can help to talk to an IVF lawyer when the records point to more than a known limit: a result that cannot be traced to the right embryo, a report that changed without explanation, or a promise about accuracy that shaped a decision you cannot take back. A claim review usually looks at:

• Which type of PGT was ordered, and what the lab report says it could and could not detect
• Chain-of-custody records linking each biopsy tube to each embryo
• What the consent forms and counseling notes say you were told
• Whether prenatal testing was offered, and what it showed
• What was done with embryos after the results, and who decided
• Marketing materials you saw before agreeing to testing
• Dates, which control filing deadlines

Who may be responsible for a PGT error

Responsibility depends on where a problem started, and it is never presumed. Depending on the facts, a review may look at:

• *The genetic testing laboratory*, for sample handling, analysis and reporting
• *The fertility clinic and embryology lab*, for biopsy, labeling and tubing of samples
• *The physician or genetic counselor*, for how results and limits were explained
• *A company that marketed the test*, for claims made in ads, websites or consent materials

Filing deadlines for PGT claims

Time limits for PGT claims depend on the state, the type of claim and when the problem was or should have been found. In Arizona, for example, injury claims, including medical malpractice, generally must be filed within two years after the cause of action accrues12. Arizona also requires a written statement, filed with a claim against a health care professional, on whether expert testimony is needed, and if it is, a preliminary expert opinion affidavit served with the initial disclosures13. Other states use different periods and pre-suit steps, and a claim about advertising may follow a different clock than a malpractice claim. An attorney can check the rules that apply to you.

Tell Us Your Story →

Records that help a PGT claim review

Records worth gathering

Testing records

• PGT lab reports for every embryo
• Test requisition and order forms
• Biopsy and tubing logs with embryo numbers
• Any retest or second-opinion results

Clinic and counseling records

• Signed consent forms for IVF and PGT
• Genetic counseling notes or summaries
• Embryo disposition forms
• Emails or portal messages about results

Pregnancy and later records

• Prenatal screening, CVS or amniocentesis results
• Pathology from any pregnancy loss
• Newborn or pediatric genetic testing
• Bills, claims and explanation of benefits forms

What happens after you contact CBW Law

How a review works

1. You tell us what happened

   Share the test type, the results you received and what happened next. Rough dates are enough to start.

2. We review the records

   With your permission, we gather lab, clinic and counseling records and line them up against each other.

3. We look at limits and errors

   We compare what happened with the test’s known limits and the steps a lab and clinic were expected to take.

4. We explain your options

   We tell you what we found, whether we see a basis for a claim, and how deadlines may affect next steps.

Plain English

Medical, Health & Insurance

Genetic test reports and insurance bills use their own vocabulary. These short definitions may help when you read your records.

Test types

PGT-A

Testing embryos for missing or extra chromosomes1.

PGT-M

Testing embryos for a specific single-gene disorder1.

PGT-SR

Testing embryos when a parent carries a structural chromosome rearrangement, such as a translocation1.

Prenatal diagnostic test

A test in pregnancy, such as CVS or amniocentesis, that checks fetal or placental cells for specific conditions14.

Result terms

Euploid

Having the expected number of chromosomes.

Aneuploid

Having a missing or extra chromosome.

Mosaic

A biopsy reading that suggests a mix of cells with different chromosome patterns.

False positive / false negative

A result that wrongly reports a problem, or wrongly reports none. ACOG says both are possible with any PGT1.

Residual risk

The chance that a result is wrong even after testing done correctly.

Lab terms

Embryo biopsy

Removing a few cells from an embryo so they can be tested.

Allele drop-out

When one copy of a gene fails to show up in testing, which can cause a wrong call4.

Contamination

Outside DNA getting into a sample and mixing with the embryo’s DNA4.

Chain of custody

The record showing who handled a sample, and when, from biopsy to report.

Insurance & billing

Add-on

An optional service sold alongside IVF, often billed separately.

Explanation of benefits (EOB)

A statement from your insurer showing what was billed, paid and left for you to pay.

Out-of-network lab

A lab that has no contract with your health plan, which can mean a separate, higher bill.

Prior authorization

Approval an insurer may require before it will pay for a test or procedure.

Questions

Frequently asked PGT results questions

Short answers to questions families often ask about PGT results and their limits.

If my “normal” embryo did not lead to a baby, does that mean the test was wrong?

Not necessarily. Many euploid embryos do not result in a live birth. In one 2026 study, about 60% of single transfers of euploid embryos ended in a live birth6. A failed transfer or a pregnancy loss can happen even when the test was done and reported correctly. A review looks for signs that something specific went wrong, such as a sample tied to the wrong embryo.

How accurate is PGT-A?

A 2025 review of 109 studies found the misdiagnosis rate after transfer of a euploid embryo was 0.2%, and that aneuploid calls held up about 89% of the time against the rest of the embryo. Mosaic results were much less reliable3. What a test can detect also depends on the platform the lab uses5, so the lab’s own report matters.

What is a mosaic embryo, and should it have been discarded?

A mosaic result means the biopsy suggested a mix of normal and abnormal cells. In one 2026 study, 53.2% of transfers of embryos with mosaic-range readings ended in a live birth6, and advice on how to handle mosaic embryos differs between professional groups7. Whether discarding one was reasonable depends on what you were told and what you agreed to. If you were not counseled on your options, that is worth reviewing.

Should I have been offered prenatal testing after PGT?

ACOG says prenatal screening or diagnostic testing should be offered to everyone who had PGT-A, and that this is especially important after PGT-M or PGT-SR done without PGT-A1. If no one discussed prenatal testing with you, note that when you gather your records.

Can PGT-M miss the condition it was looking for?

Yes. ESHRE lists allele drop-out, contamination and undetected recombination as causes of PGT-M misdiagnosis, and expects labs to report a residual risk4. Whether a missed diagnosis was a known limit or an error depends on the method, the lab’s controls and the records.

Does PGT-SR tell me whether an embryo carries my balanced translocation?

Often it does not. ESHRE notes that some common methods cannot tell a typical embryo from a balanced carrier, though haplotype-based methods can5. Your report or counseling notes should say which method was used.

Is a PGT lawsuit the same as a PGT-A class action?

No. The PGT-A class actions in the news focus on how tests were marketed and are at early stages as of October 2026811. An individual claim may involve a specific lab error, a sample mix-up or a counseling failure. A lawyer can explain which kind of claim, if any, fits your facts.

How is PGT different from polygenic embryo screening?

PGT-A, PGT-M and PGT-SR look at chromosomes or specific known gene changes. Polygenic screening, often called PGT-P, estimates risk for common conditions from many small genetic differences. It raises separate questions, covered on our page on polygenic embryo screening (PGT-P).

Does an unexpected result mean I have a case?

No. PGT has known limits, and an unexpected outcome alone does not show negligence or a misleading claim. A claim usually needs evidence of a specific error or misstatement and harm that followed from it. An attorney can review the records and tell you whether they support a claim, and you can learn more on our IVF and fertility treatment injuries page.

How long do I have to act?

It depends on your state and the type of claim. Arizona, for example, generally allows two years for injury claims, including medical malpractice12. Some deadlines are shorter, and some start before you know there was a problem, so it helps to ask early.

Tell Us Your Story

PGT can lower some risks, but it reads a small sample, has known limits and cannot promise a pregnancy or a healthy child. A claim usually depends on whether a lab or clinic made a specific error, or whether you were given information about the test that was not accurate.

If you believe a testing error or misleading information affected your treatment, CBW Law can review what happened and explain what we find. Tell us your story when you are ready.

Tell Us Your Story →Call (800) 476-2416

This page is general information about PGT results and testing limitations. It is not legal or medical advice and does not create an attorney-client relationship. An unsuccessful cycle, a complication, an embryo loss or a testing limitation does not, by itself, establish that anyone was negligent. No outcome can be promised in any case.