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Does Medicare cover a blood test for colon cancer?

Yes. Medicare Part B covers what it calls a "blood-based biomarker" screening test for colorectal cancer once every 3 years at no cost to you when the provider accepts assignment, if you are between 45 and 85, have no symptoms of colorectal disease, and are at average risk. Medicare.gov adds two words to the schedule, "if available," and this page explains what the record says about them.

This page is about the blood test. For how often Medicare pays for other blood work and screening tests, see our free chart of Medicare's screening schedules.

What the test is

Medicare's provider chart lists the billing code as G0327, described as "Colorectal cancer screening; blood-based biomarker," and also lists a second code, 0537U, for a plasma cell-free DNA test. It is a screening test done on a blood sample, and it sits under the same national coverage rule as the stool DNA test, NCD 210.3. The rule calls both of them "Non-Invasive Biomarker Tests."

Who qualifies

Medicare.gov lists three conditions, and you have to meet all of them: "You're between 45–85," "You show no symptoms of colorectal disease," and "You're at average risk for developing colorectal cancer."

The national coverage rule says what those words mean. No symptoms means "no signs or symptoms of colorectal disease including but not limited to lower gastrointestinal pain, blood in stool, positive non-invasive biomarker colorectal cancer screening test." Average risk means "no personal history of adenomatous polyps, colorectal cancer, or inflammatory bowel disease" and "no family history of colorectal cancers or adenomatous polyps, familial adenomatous polyposis, or hereditary nonpolyposis colorectal cancer." The rule also says you must be "Provided with information about the test performance and the importance of a follow-on colonoscopy if the test returns a positive result."

The provider chart covers the stool DNA test and the blood test in one row: "Patients with Medicare Part B who meet these criteria: Aged 45–85 years / Asymptomatic / At average colorectal cancer risk."

How often Medicare pays, and what "if available" means

Medicare.gov: "Once every 3 years (if available)." The provider chart: "Once every 3 years." Medicare.gov does not explain the words "if available." Here is what the published record shows.

• The rule has been in force since 2021. The previous version of NCD 210.3 said: "Effective for dates of service on or after January 19, 2021, a blood-based biomarker test is covered ... once every 3 years," for a test with "sensitivity greater than or equal to 74% and specificity greater than or equal to 90%." So Medicare wrote the coverage rule before a test existed to fill it.
• The FDA authorized a test in 2024. The FDA's record for premarket approval P230009 lists "Shield," made by "Guardant Health, Inc.," with a decision date of July 26, 2024. Its stated use: "Shield is intended for colorectal cancer screening in individuals at average risk of the disease, age 45 years or older."
• CMS's 2026 memo treats it as meeting the new standard. The decision memo behind the June 2026 rule reports Shield at "83.1% sensitivity for detecting CRC" and a specificity of "89.9%," figures the memo counts as meeting the rule's Criteria 2.
• There is a code to bill it. G0327, quoted above.

So a blood test exists that the FDA has authorized for this use, that CMS's own memo treats as meeting its standard, and that has a Medicare billing code. Whether your doctor's office or lab offers it is a question for them.

What you pay

Medicare.gov: "You pay nothing for this test if your doctor or other health care provider accepts assignment." The provider chart: "No copayment, coinsurance, or deductible."

If the test is positive

Medicare.gov: "If you get a positive result after a blood-based biomarker screening test, Medicare also covers a follow-up colonoscopy as a screening test." Medicare.gov's colonoscopy page gives the cost: "If your doctor or other health care provider accepts assignment, you pay nothing for the screening test(s), including follow-up colonoscopies you get after a positive result from a Medicare-covered blood-based biomarker test or non-invasive stool-based test."

CMS's decision memo says the same: "The follow-on colonoscopy after a positive non-invasive stool-based or blood-based CRC screening test is considered a complete CRC screening" and "is not subject to cost sharing."

One note for anyone who reads Medicare's provider chart. Its sentence on follow-up colonoscopies names only the stool tests: "If the patient gets a positive result from an initial non-invasive screening test (FOBT or MT-sDNA test), we also cover a follow-up colonoscopy as a screening test." It does not mention the blood test. Medicare.gov and the decision memo, both quoted above, do include it. If a billing office points to the chart, the medicare.gov page and the memo are the documents that include the blood test.

If a polyp or other tissue is removed during that colonoscopy, Medicare.gov says you pay "15% of the Medicare-approved amount." Our colonoscopy guide explains that rule.

What changed in June 2026

NCD 210.3 was rewritten. The new version says "Effective Date of this Version 06/08/2026" and "Implementation Date 01/04/2027." The previous version, in force from January 1, 2023 to June 8, 2026, had one section for the stool DNA test and a separate one for the blood test, each with its own performance numbers. The new version replaces both with one section, "Non-Invasive Biomarker Tests," and one set of standards for any test under it.

A test is now covered when it is "FDA market authorized and indicated for colorectal cancer screening," meets "the requirements of the FDA-required post-approval study," is "processed in a CLIA certified laboratory," and can "meet EITHER Criteria 1, a sensitivity of greater than or equal to 90% and a specificity greater than or equal to 87%, OR Criteria 2, a sensitivity of greater than or equal to 79% and a specificity of greater than or equal to 90% in the detection of colorectal cancer compared to the recognized standard (accepted as colonoscopy at this time), based on the FDA labeling." The memo sets no separate standard for blood tests versus stool tests.

The parts that matter to you did not move. The new section still says "Age 45 to 85 years," still requires "Asymptomatic" and "At average risk," and still says the tests "are covered once every 3 years." The rule itself does not name any product, list any billing code, or say what you pay; those come from medicare.gov and the provider chart.

What the Preventive Services Task Force says

The U.S. Preventive Services Task Force's May 18, 2021 recommendation on colorectal cancer screening "does not include serum tests, urine tests, or capsule endoscopy ... because of the limited available evidence." A serum test is a blood test. So the blood test's Medicare coverage rests on Medicare's own rule, NCD 210.3, and not on a Task Force grade. That is a statement about where the rule comes from, not about whether the test is a good choice; this page does not say which screening you should have.

If you have Medicare Advantage

A plan can have its own rules about which lab you use and whether the order needs approval first. For what can and cannot change under a plan, see Medicare Advantage and lab tests.

Before you go

This is ClaraCover's checklist, built from the rules above.

1. Are you between 45 and 85, with no symptoms, at average risk? All three are required. Average risk means none of the personal or family history listed above.
2. When was your last colorectal screening of any kind? This test is paid once every 3 years. Have the date of your last stool test, blood test, or colonoscopy ready.
3. Ask whether the office offers the test and bills it as G0327. Medicare.gov's schedule says "if available," and only the office can tell you whether it is.
4. If it comes back positive, the colonoscopy is a screening. Medicare covers it as a screening test at $0 with assignment. If a billing office says otherwise, the medicare.gov page and CMS's decision memo, both quoted above, say it is.

Sources

• Medicare.gov: Blood-based biomarker tests
• Medicare.gov: Colonoscopies
• CMS: Medicare Preventive Services educational tool (MLN006559, July 2026), Colorectal Cancer Screening Tests entry
• CMS: National Coverage Determination 210.3, Colorectal Cancer Screening Tests (version 8, effective June 8, 2026)
• CMS: National Coverage Determination 210.3, version 7 (in force January 1, 2023 to June 8, 2026)
• CMS: Decision Memo CAG-00440R, Colorectal Cancer Screening Tests (June 8, 2026)
• FDA: Premarket Approval P230009, Shield (Guardant Health, Inc.), decision date July 26, 2024
• U.S. Preventive Services Task Force: Colorectal Cancer, Screening (May 18, 2021)

Checked September 27, 2026. This page explains published Medicare rules. It is not medical or insurance advice, does not say who should have this test or which screening to choose, and cannot tell you whether your own test will be covered or what your bill will be; your doctor's office and Medicare can. ClaraCover has no relationship with any test maker, provider, or plan.