LIFESTYLE
ACS Adds Shield Blood Test to Colorectal Cancer Screening Guideline
<p>The American Cancer Society added a blood test to its colorectal cancer screening guideline on Wednesday, May 27, 2026, the first time a venous draw has earned a place alongside colonoscopy and stool kits as a recommended option for adults at average risk who are 45 and older. The accepted test is Guardant Health&#8217;s Shield, cleared by the US Food and Drug Administration in July 2024.</p>
<p>Shield enters the guideline with a qualifier. The society recommends it only for patients who decline or cannot complete a colonoscopy or a stool-based test, which makes the population behind that &#8216;decline&#8217; the audience the update was written for.</p>
<h2>What ACS Changed and Who It Was Built For</h2>
<p>The <a href="https://acsjournals.onlinelibrary.wiley.com/doi/10.3322/caac.70083" target="_blank" rel="noopener">updated guideline in CA: A Cancer Journal for Clinicians</a> reaffirms that average-risk adults should begin colorectal screening at 45 and continue through 75 if life expectancy is at least 10 years. What changed is the option set. Adults can now choose, in addition to a colonoscopy or a fecal immunochemical test, a blood draw at the doctor&#8217;s office. Shield is <strong>the first venous draw to be recommended by the society for primary screening</strong>.</p>
<p>Two stool tests also joined the list. Cologuard Plus, the next-generation update of Exact Sciences&#8217; multitarget stool DNA assay, <a href="https://www.exactsciences.com/newsroom/press-releases/fda-approves-exact-sciences-cologuard-plus-test" target="_blank" rel="noopener">received FDA approval on October 4, 2024</a>. ColoSense, developed by Geneoscopy, was cleared in May 2024. Both are at-home collection kits that look for molecular markers and hidden blood, then ship to a central lab.</p>
<p>The reasoning is direct. &#8220;There are a lot of people who can&#8217;t or won&#8217;t do a colonoscopy, or the idea of collecting their own stool for testing, they just won&#8217;t do,&#8221; said William Dahut, chief scientific officer of the American Cancer Society. &#8220;Having more options hopefully will allow more people to be screened to find cancers earlier on, and we&#8217;ll be able to cure more patients.&#8221;</p>
<p>The gap Dahut is talking about is large. The most recent <a href="https://www.cdc.gov/pcd/issues/2025/25_0175.htm" target="_blank" rel="noopener">baseline estimates from the Centers for Disease Control and Prevention</a> put up-to-date colorectal screening among adults aged 45 to 75 at 63.5% in 2023. Roughly one in three eligible Americans is therefore behind on a test that, if a tumor is caught at stage I or II, predicts a five-year survival rate above 90%.</p>
<figure class="wp-block-image aligncenter featured-image" style="margin:1.5em auto;text-align:center;"><img class="aligncenter" src="https://budgyapp.com/wp-content/uploads/2026/05/blood-based-colorectal-cancer-screening-test-added-to-american-cancer-society-gu.webp" alt="Blood-based colorectal cancer screening test added to American Cancer Society guideline." style="width:100%;max-width:800px;height:auto;border-radius:8px;display:block;margin:0 auto;" /><figcaption style="text-align:center;font-size:0.85em;color:#888;margin-top:0.5em;">Blood-based colorectal cancer screening test added to American Cancer Society guideline.</figcaption></figure>
<h2>The Three New Tests Compared</h2>
<p>The three additions sit at very different points on the convenience-versus-sensitivity curve. A colonoscopy still anchors the top of that curve. Among at-home options, the gap between blood and stool DNA shows up cleanly in the trial data.</p>
<table>
<thead>
<tr>
<th>Test</th>
<th>Sample type</th>
<th>FDA cleared</th>
<th>Cancer sensitivity</th>
<th>Advanced precancer sensitivity</th>
<th>Frequency</th>
</tr>
</thead>
<tbody>
<tr>
<td>Shield (Guardant Health)</td>
<td>Blood draw</td>
<td>July 2024</td>
<td>83%</td>
<td>13%</td>
<td>Every 3 years</td>
</tr>
<tr>
<td>Cologuard Plus (Exact Sciences)</td>
<td>Stool, at home</td>
<td>October 2024</td>
<td>93.9%</td>
<td>43.4%</td>
<td>Every 3 years</td>
</tr>
<tr>
<td>ColoSense (Geneoscopy)</td>
<td>Stool, at home</td>
<td>May 2024</td>
<td>93%</td>
<td>45%</td>
<td>Every 3 years</td>
</tr>
<tr>
<td>Colonoscopy</td>
<td>Endoscopic exam</td>
<td>Standard procedure</td>
<td>Above 95%</td>
<td>Above 95%</td>
<td>Every 10 years</td>
</tr>
</tbody>
</table>
<p>Stool DNA tests pick up more than nine in ten cancers and roughly four in ten advanced adenomas, the polyps that, if removed, prevent a cancer from forming. Shield catches <strong>83% of cancers</strong>, the rate published in the ECLIPSE trial in The New England Journal of Medicine in March 2024, but the same dataset showed it identified only 13% of advanced precancerous lesions. A colonoscopy, by contrast, sees the lesion and removes it in one visit.</p>
<p>For a patient who would otherwise skip the year entirely, the trade-off changes meaning. Detection at any stage beats detection at no stage.</p>
<h2>The Sensitivity Gap Behind the Convenience</h2>
<p>Most colorectal cancers begin as a polyp. The cell line takes between five and fifteen years to turn malignant, and the entire reason colonoscopy is the standard is that the endoscopist can spot the polyp and snip it during the same procedure. Stool DNA tests can flag the molecular signature of a precancer; a positive result then triggers a follow-up colonoscopy. Either path catches the disease before it becomes a disease.</p>
<p>Blood-based screening sits one step further out. Tumors shed cell-free DNA into the bloodstream only once they reach a certain size, which is why Shield&#8217;s sensitivity drops sharply for the smaller, precancerous lesion. The ECLIPSE expansion data put <strong>advanced adenoma sensitivity at 13%</strong>.</p>
<p>Ursina Teitelbaum, professor of gastrointestinal oncology at the University of Pennsylvania and section chief of gastrointestinal cancers at Penn Medicine, framed the trade-off in written comments. She called the guideline forward-thinking and reality-based.</p>
<blockquote>
<p>The test remains another option, albeit imperfect since it may miss early-stage cancers and precancerous lesions. It all harkens, though, to &#8216;perfect is the enemy of good,&#8217; and these new guidelines acknowledge the need to broaden the capture of screening, particularly in younger, vulnerable populations.</p>
</blockquote>
<p>Teitelbaum was not part of the panel that wrote the updated guideline. The same logic appears in the guideline text itself: the authors recommend blood-based tests only for patients who decline or do not complete preferred screening. Scott Kopetz, gastrointestinal medical oncologist at The University of Texas MD Anderson Cancer Center, made the point in an email that patients otherwise willing to undergo a colonoscopy or stool test should not swap to a blood draw.</p>
<h2>Why Newly Eligible Adults Are the Hidden Variable</h2>
<p>The screening calendar was lowered from 50 to 45 in 2021, when the US Preventive Services Task Force and the American Cancer Society aligned on the earlier start in response to rising rates of young-onset disease. Five years later, that newly eligible cohort is the demographic least likely to have followed through.</p>
<p>Adults aged 45 to 49 sit at a <strong>20% up-to-date screening rate</strong>, by far the lowest band in the 45-to-75 window the guideline covers. The roughly 35% of eligible Americans who remain behind on screening is concentrated heavily in that early cohort, in Asian Americans (50% screened), and in the uninsured (21% screened).</p>
<p>A blood draw at an annual physical sidesteps several of the barriers that keep that group out of the system:</p>
<ul>
<li>No bowel prep, no clear-liquid diet, no day off work for sedation recovery</li>
<li>No fecal sample to collect at home and ship</li>
<li>A test that can be ordered, drawn, and billed in the same primary-care visit</li>
<li>A result that arrives before the patient has time to second-guess the appointment</li>
</ul>
<p>A 46-year-old who keeps postponing a first colonoscopy because of squeamishness is the patient who will say yes to a venous draw. The clinical question is whether 83% sensitivity for cancer, with 13% sensitivity for the precancerous lesion, captures enough of that group&#8217;s eventual disease to be worth recommending over no test at all. The authors of the updated guideline argue that it does, on the math that a moderately sensitive test most refusers will complete outperforms a near-perfect test the same patients will not.</p>
<h2>Guardant Health Gets a Coverage Pathway</h2>
<p>The clinical guideline matters most to patients, but it travels straight into the reimbursement code books. The Centers for Medicare and Medicaid Services pays for blood-based colorectal screening every three years for average-risk adults 45 and older when the test is FDA-approved and listed in major society guidelines. Shield was <a href="https://investors.guardanthealth.com/press-releases/press-releases/2025/Guardant-Health-Receives-ADLT-Status-From-CMS-for-Shield-Blood-Test/default.aspx" target="_blank" rel="noopener">granted Advanced Diagnostic Laboratory Test status by CMS in 2025</a>, setting an initial reimbursement of $1,495 per test. The American Cancer Society&#8217;s update gives Shield the second leg of the coverage equation.</p>
<p>The Shield approval rests on the ECLIPSE study, a registrational trial that <a href="https://www.cancer.gov/news-events/cancer-currents-blog/2024/shield-blood-test-colorectal-cancer-screening" target="_blank" rel="noopener">enrolled more than 20,000 average-risk patients</a> and published in The New England Journal of Medicine in March 2024. Shield&#8217;s most recent algorithm version, Shield V2, reports 84% sensitivity for cancer at 90% specificity, with stage I sensitivity of 62%. Guardant Health has said its next-generation test, in development, targets improved precancer detection.</p>
<p>Kopetz, the MD Anderson oncologist, predicted the category will keep expanding. &#8220;This is the first blood-based test, but won&#8217;t be the last, and the hope is that future tests will continue to reduce the barriers to access to effective screening and will have improved performance,&#8221; he wrote. &#8220;The technology will only improve from here.&#8221; Freenome and Exact Sciences both have blood-based colorectal assays in trials, and several other companies are in earlier-stage development; none of them carry the guideline placement Shield now has. If the second-generation tests close the precancer-sensitivity gap to within range of stool DNA, the third-tier fence in the current guideline becomes harder to justify.</p>
<h2>Frequently Asked Questions</h2>
<h3>Who Qualifies for the Shield Blood Test under the New Guideline?</h3>
<p>Adults aged 45 and older at average risk for colorectal cancer who have declined or have not completed a colonoscopy, a fecal immunochemical test, or a stool DNA test. The blood test is not recommended for patients with a family history of colorectal cancer, prior polyps, inflammatory bowel disease, or other higher-risk conditions. Those patients should continue with colonoscopy on the schedule their physician sets.</p>
<h3>How Often Should the Shield Test Be Repeated?</h3>
<p>Every three years if the result is negative. A positive Shield result must be followed by a diagnostic colonoscopy, the same protocol that applies after a positive stool-based test. The follow-up colonoscopy is what catches the lesion and, in many cases, removes it.</p>
<h3>Is the Shield Test Covered by Medicare or Private Insurance?</h3>
<p>Yes for Medicare Fee-for-Service patients age 45 and older, with $0 out-of-pocket cost during the current ADLT pricing period. Medicare Advantage co-pays and deductibles vary by plan. Private insurance coverage is rolling out; most commercial plans align with major society guidelines, so the American Cancer Society update is expected to expand coverage over the next several quarters. Patients should confirm with the ordering office before the blood draw.</p>
<h3>Does a Negative Blood Test Mean I Do Not Have Colorectal Cancer?</h3>
<p>No. A negative Shield result lowers the probability but does not rule out the disease. The test misses roughly 17% of cancers and the majority of advanced precancerous polyps. Patients with new symptoms (rectal bleeding, persistent change in bowel habits, unexplained weight loss, iron-deficiency anemia) should consult a clinician regardless of a recent negative screening result.</p>
<h3>How Does the Cost Compare with a Colonoscopy?</h3>
<p>Shield&#8217;s list cash-pay price is $1,495 per test. A screening colonoscopy in the United States typically ranges between $1,250 and $4,800 depending on facility and insurance contract. Cologuard Plus carries a list price under $1,000. Out-of-pocket cost for any of these depends on coverage, deductible, and whether a follow-up colonoscopy is needed.</p>
<h3>Where Can I Read the Full Updated Guideline?</h3>
<p>The full update is published open-access in CA: A Cancer Journal for Clinicians, the peer-reviewed journal of the American Cancer Society. <a href="https://pressroom.cancer.org/colorectal-cancer-screening-guideline-update-2026" target="_blank" rel="noopener">The society&#8217;s pressroom summary</a> outlines the rationale and lists all recommended testing options with their intervals.</p>
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<p><strong><em>Disclaimer:</em></strong> <em>This article is for informational purposes only and does not constitute medical advice. Cancer screening decisions involve personal risk factors, family history, and clinical considerations that vary between patients; consult a licensed physician or qualified healthcare professional before choosing or changing a screening test. Figures, pricing, and guideline language are accurate as of publication on May 28, 2026.</em></p>