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What are secondary findings from genetic testing?
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Testing

What are secondary findings from genetic testing?

Secondary findings are genetic variants identified during testing that are unrelated to the primary purpose for which the test was originally ordered.

Understanding Secondary Findings

When a clinician orders a test to find the cause of a specific condition, they may use whole exome sequencing (sequencing all DNA that provides instructions for proteins) or whole genome sequencing (sequencing all DNA building blocks). Because these tests analyze vast amounts of genetic data, they may identify a secondary finding—a variant associated with a condition other than the one being investigated.

Some individuals with a secondary finding may not yet show symptoms but could be at risk for developing a condition later in life, such as a BRCA1 gene variant associated with cancer risk. Others may receive a genetic explanation for a condition they already have, such as high cholesterol linked to an LDLR gene variant.

ACMG Recommendations

The American College of Medical Genetics and Genomics (ACMG) recommends that laboratories performing whole exome or genome sequencing report specific secondary findings. As of 2021, the list includes 73 genes associated with conditions that meet specific criteria:

  • A definable set of clinical features.
  • The possibility of early diagnosis.
  • Availability of a reliable clinical genetic test.
  • Effective intervention or treatment options.

The goal is to provide medical benefit through prevention or better management. Variants of unknown significance are not reported as secondary findings.

Considerations for Patients

While secondary findings can guide preventive care or early treatment, they may also lead to unexpected stress and additional health costs. Individuals undergoing whole exome or whole genome sequencing have the option to "opt out" of the analysis of these 73 genes if they prefer not to receive this information.

Frequently Asked Questions

Secondary findings are genetic variants identified incidentally during broad testing, such as whole exome or whole genome sequencing, that are unrelated to the primary condition being investigated. They occur because these comprehensive tests analyze vast amounts of DNA, increasing the likelihood of detecting variants associated with other health conditions.
Yes, individuals undergoing whole exome or whole genome sequencing have the option to opt out of the analysis of the 73 ACMG-recommended genes. This decision should be made before testing begins, as it determines whether the laboratory will screen for and report these incidental findings.
Secondary findings can provide actionable information for preventive care or early treatment, such as increased cancer screening or medication adjustments for cholesterol. However, they may also cause unexpected psychological stress or lead to additional medical costs and procedures, so it is important to discuss potential implications with a genetic counselor before testing.
The American College of Medical Genetics and Genomics (ACMG) recommends reporting variants in 73 specific genes. These genes are associated with conditions that have definable clinical features, allow for early diagnosis, have reliable testing methods, and offer effective interventions or treatments, such as certain hereditary cancers or cardiovascular risks.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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