Secondary findings are results about genes unrelated to why you were tested, most often variants linked to serious but preventable or treatable conditions. They are most likely with exome or genome sequencing. In clinical sequencing you can usually choose whether to receive them, so the best time to decide is before testing.
A secondary finding is not a diagnosis. It is a prompt to confirm the result and talk to a clinician.
Primary, secondary and incidental: what the words mean
The terms are used loosely, so it helps to pin them down.
- Primary findings answer the question you tested for, such as the cause of a child's symptoms.
- Secondary findings are variants in genes unrelated to the reason for testing that a lab looks for on purpose, using an agreed list.
- Incidental findings are unplanned discoveries that turn up while looking for something else.
MedlinePlus describes secondary findings as results about genes unrelated to why the test was ordered, most likely with whole exome or whole genome sequencing because they examine so many genes. Some people with such a finding have no symptoms yet but may develop the condition later. Others already have a diagnosed condition, and the result points to its genetic cause.
What the ACMG list covers
The best-known standard is the American College of Medical Genetics and Genomics (ACMG) secondary findings list. Its current version, SF v3.3, was released on July 9, 2025, and applies to reporting from clinical exome and genome sequencing. It lists more than 80 genes grouped into cancer predisposition, cardiovascular conditions, inborn errors of metabolism and a small set of other conditions. Examples include BRCA1 for hereditary breast and ovarian cancer, MYH7 for hypertrophic cardiomyopathy and LDLR for familial hypercholesterolemia.
Version 3.3 is a minor update that added three genes: ABCD1, CYP27A1 and PLN. The working group considered but did not add GCK, RUNX1 and SLC4A1, and deferred a decision on ADA2. Because lists are revised, some older pages, including MedlinePlus at the time we read it, still describe an earlier 73-gene version.
Reporting rules are strict. Genes are chosen for conditions that can be recognised early, have reliable genetic testing and respond to prevention or treatment. Variants must be known to cause disease, so variants of uncertain significance are not reported. For dominant conditions, one pathogenic or likely pathogenic variant is reportable, and for recessive ones two are needed.
If you want to see what these conditions look like in practice, our guides to familial hypercholesterolemia, Lynch syndrome and long QT syndrome cover conditions of the type these lists target.
Reasons people want to know
- Prevention is possible. The point of the list is medical benefit: a finding can lead to earlier screening, preventive care or treatment.
- Family benefit. A confirmed finding can let relatives be tested for the same variant.
- Peace of mind about a plan. Some people prefer knowing and planning to wondering.
Reasons people choose not to
- Emotional weight. MedlinePlus notes that results can bring added costs and emotional stress for the person and their family.
- Follow-up burden. A finding can mean confirmatory testing, ongoing screening and appointments.
- Insurance questions. In the US, federal law bars health insurers and most employers from using genetic information, but it has gaps for life, disability and long-term care insurance. See our GINA explainer and life insurance disclosure guide.
- The right not to know. Some people deliberately avoid knowing about conditions they cannot prevent. Our post on Huntington's disease predictive testing shows how real that preference is.
Plan for the family. A finding about you can implicate your relatives too. If you receive one, you may need to decide whether and how to tell them. Read how one relative's test affects the family.
What "no secondary findings" does and does not mean
A clean result is reassuring about a short list of genes, not about your health as a whole. ACMG describes the list as a minimum set for opportunistic screening, not a replacement for diagnostic testing based on symptoms or family history. Many hereditary conditions are not on the list at all, and rare or complex variants may not be detected or classified. Our guides to cancer risk testing and uncertain variants explain the gaps.
Can you choose?
In clinical sequencing, yes. MedlinePlus states that people having exome or genome sequencing can opt out of analysis of the secondary-finding genes, so they will not receive those results. Consumer providers differ, so ask whether such a report is included, optional or unavailable before you buy, using the list in our pre-purchase questions.
Questions to settle before you test
- Would I want to know about a serious but treatable risk, even with no symptoms?
- What would I do with it? Could I act on the information, and would I want to?
- Who else would be affected, and would I want to tell them?
- How do I feel about insurance and privacy? Check protections where you live.
- Can I change my mind? Ask whether you can opt in later, since the raw data does not disappear. See why your genome needs reanalysis.
If you are unsure, a session with a genetic counselor can help, as we describe in do you need a genetic counselor.
Bottom line
There is no universally right answer. Some people value the early warning, and others value not carrying it. What matters is making the choice on purpose, before the report exists. If you opt in and receive a finding, treat it as a lead to confirm in a clinical laboratory with a clinician, not as a diagnosis from a consumer report.
Common questions
What is a secondary finding in genome sequencing?
It is a result about a gene unrelated to the reason you were tested, usually from a list of genes linked to serious conditions where early action can help. It is most likely with exome or genome sequencing.
Can I opt out of secondary findings?
In clinical exome or genome sequencing, generally yes. MedlinePlus states that people can opt out of analysis of the secondary-finding genes. Consumer providers differ, so ask before you buy.
What is the ACMG secondary findings list?
It is a minimum list of genes that the American College of Medical Genetics and Genomics recommends laboratories report on in clinical exome and genome sequencing. The current version, SF v3.3, was released on July 9, 2025.
Does having no secondary findings mean I am healthy?
No. It means no reportable variants were found in a limited gene list. It does not rule out other genetic conditions, and it is not a substitute for testing based on your symptoms or family history.
Are secondary findings the same as variants of uncertain significance?
No. Secondary findings reported under the ACMG list involve variants known to cause disease, while variants of uncertain significance are not reported. They are separate topics, though both can appear in a genome report.
Sources and verification
Verified October 2026 against the ACMG release and list and MedlinePlus. MedlinePlus still described the 2021 version of the list when we read it, so we use ACMG's 2025 update for current details. The statement that the list has more than 80 genes follows the ACMG table; the ACMG release itself does not state a total. Confirm any consumer provider's approach on its own pages.
Medical disclaimer. GenomeTesting.org publishes educational content about genetics and consumer genomic testing. Nothing here is medical advice, a diagnosis, or a substitute for care from a qualified clinician or genetic counsellor. Decisions about testing, treatment, or interpreting your own results should be made with a healthcare professional who can see your full history.