By: Sara Pirzadeh-Miller, MS, CGC
Reviewed by: Sandra Darilek, MS, CGC on 7/27/2026

One blood test with the ability to screen for many types of cancer at once? Twenty years ago, that seemed like science fiction, but today it is a reality. When considering the cancer screening options that are available (or not available) for many types of cancer, a blood test can seem very appealing.

This is called multicancer early detection (MCED) testing and is an exciting development in cancer screening options. With that excitement comes important questions about the benefits, risks and limitations of testing that can help people make informed healthcare decisions.

What are MCED tests?

MCED tests are blood tests that screen for early signs of different types of cancer.

Cells in the body, including cancer cells, release small pieces of genetic material, or DNA, into the blood. MCED tests work by identifying these cancer cell patterns when a cancer is very early in its development.

Importantly, MCED tests do not replace other methods of cancer screening, such as mammograms for breast cancer or colonoscopies for colon cancer. However, they may be used alongside regular recommended cancer screenings. 

What are the potential benefits?

Some cancers do not yet have a standard screening option. MCED tests can look for signs of many cancer types at once with a simple blood test. People may be more comfortable and more likely to get a blood test than other types of screening tests.

What are the risks and limitations?

It is important for people to understand what an MCED test can and cannot tell them.

• A positive result, meaning a cancer signal was detected by the blood test, does not mean with 100% certainty that there is cancer present. More tests would have to be done to understand if cancer is present, such as lab tests, imaging, or other procedures. It’s possible that these follow-up tests will not detect cancer. Information like this could cause stress, anxiety, and fear.
• On the other hand, a negative result, which means no cancer signal detected, does not rule out cancer. The test is not equally sensitive for all types of cancer. Some cancers may not release enough easily identifiable genetic material into the blood or may not yet be detectable through MCED testing.

We also do not yet know the true long-term benefits of MCED testing. Does it reduce cancer deaths? Does this testing improve long-term health outcomes? Research on this technology will help us understand this in the future.

How genetic counselors can help

MCED testing can be complex, and this is where genetic counselor skills shine. They can help before, during and after testing.

Genetic counselors are master’s-level healthcare practitioners who are trained to translate complex healthcare information into understandable facts and help people handle difficult information.

Before testing: Understanding your options

Genetic counselors are trained to help people understand medical tests in a way that makes sense for everyone. They can explain what the MCED test is, the benefits and limitations of testing, and the possible medical and emotional impacts of testing. They also review personal and family cancer history and help someone understand if inherited cancer risk testing might also make sense to get more information about a person’s cancer risk factors.

During testing: Information and support

Genetic counselors can explain what the laboratory is analyzing, what the results may mean, what they do not mean and what the next steps in medical care could look like. They are also trained in counseling skills to help people prepare for the emotions this testing can bring.

After testing: Putting it all together

If a cancer signal is detected, a positive result, genetic counselors can explain the result in understandable language, review follow-up testing options, coordinate with other healthcare practitioners and help people understand what we know and do not know based on the result.

If no signal is detected, a negative result, genetic counselors can review typical cancer screening that is still recommended and, if not already done, they would also review if a personal or family history of cancer would suggest inherited cancer risk testing as an option for personalized cancer risk assessment.

 Find a genetic counselor near you

Genetic counselors are genomic healthcare specialists. They have specialized training that applies to any genomic technology, such as MCED testing.

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