The short answer
Molecular residual disease, or MRD, means tumor DNA fragments found in blood after surgery or treatment meant to cure, when scans look clear. FDA calls it a marker of higher relapse risk, not yet a validated basis for changing treatment. This page explains the two assay types and what to ask.
molecular residual disease has a specific meaning in ctDNA reports, clinical trials, and some FDA-authorized companion diagnostic contexts.
The phrase alone is not the whole diagnosis or treatment plan.
The next step depends on the full report, prior tests, symptoms, and your cancer history.
Ask what the finding changes, what remains uncertain, and when you will review the plan.
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This page is for people who have seen "molecular residual disease" or "MRD" on a test report after cancer treatment. It explains the term, what the blood test looks for, and what to ask.
The phrase has an official home
Molecular residual disease, usually shortened to MRD, appears in FDA guidance. The guidance is titled "Use of Circulating Tumor Deoxyribonucleic Acid for Early-Stage Solid Tumor Drug Development." FDA issued it as final in November 2024. It covers assay considerations for finding MRD in people treated with curative intent.
What the blood test looks for
The test looks for circulating tumor DNA, or ctDNA. This is DNA from tumor cells that is found in the plasma, the liquid part of blood. When ctDNA is found after treatment meant to cure, in someone whose scans look clear, it is called MRD.
What it does and does not tell you
A detected result may point to a higher risk that cancer will return. That does not prove it will. It also does not show that changing treatment will help. This page could not confirm from an opened source how strong the evidence is for each cancer type. Ask your team how your result will be used.
Tumor-informed and tumor-naive tests
Some MRD tests are built from your own tumor tissue. Others use a fixed panel for everyone. Ask which type was run and whether your tumor was sequenced for it. Ask when the blood was drawn, and whether a sample was taken before treatment.
The other MRD
Blood cancers use the same initials for minimal or measurable residual disease. That test counts leukemia cells left after treatment. NCI says that for childhood acute lymphoblastic leukemia, genetic findings combined with MRD results "can define subsets of ALL with EFS rates exceeding 95% and, conversely, subsets with EFS rates of 50% or lower." EFS means event-free survival. Check which kind of MRD your report means.
Questions worth asking
- Was my test tumor-informed or tumor-naive?
- When was the blood drawn compared with my surgery or treatment?
- If it is detected, what would we do differently, and is that from a trial, a guideline, or a judgment call?
- If it is not detected, does my scan schedule change?
- Is there a clinical trial that uses this result?
If you have fever of 100.4 F (38 C) or higher, new severe pain, or trouble breathing, call your care team right away. Call 911 for an emergency.
Related report help
See the report hub, the report decoder, and Biomarker Testing.
Sources
Common questions
What does molecular residual disease mean?
In general, molecular residual disease usually refers to cancer-related DNA detected after curative-intent treatment when standard scans may show no visible cancer.
Does it mean cancer?
It is not a universal surveillance tool for every solid tumor; the evidence and actionability vary by cancer and test.
What should I ask next?
A practical next question is to ask whether the result is tumor-informed, whether it is FDA-authorized for your situation, and what action the result supports.
Questions to ask your doctor
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More words from this kind of report
Other guides in biomarker & genetic tests.
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Get urgent help
Fever of 100.4°F (38°C) or higher during chemo, severe pain, or trouble breathing: call your cancer care team right away, day or night. Call 911 for an emergency.
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Sources last checked: 2026-10-02 what this meansLast updated: 2026-10-02Next planned review: 2027-07-20
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Editorial review complete — This page completed Cancer Explained's editorial checks (sources, safety, plain language, duplication). It has not been reviewed by a physician or other healthcare professional.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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