The News

The American Cancer Society dropped updated colorectal cancer screening guidelines on Wednesday, May 27, 2026. For the first time ever, a blood test made the list.

The test is called Shield, made by California-based Guardant Health. The FDA approved it in 2024. It works by detecting DNA fragments that cancerous tumors shed into the bloodstream.

The ACS also added two new stool-based options: an upgraded version of Cologuard called Cologuard Plus, and a new FDA-approved test called ColoSense, developed by a separate biotech. The blood test is the headline, though — it's the first of its kind to earn this designation.

Why It Matters

Colorectal cancer is now the leading cause of cancer death in Americans under age 50. A disease most people associate with elderly patients is killing young adults at a rising rate.

About one-third of eligible American adults — meaning those 45 and older at average risk — are NOT up to date on their screenings, according to the American Cancer Society. That's tens of millions of people walking around unscreened for a cancer that is, in Dr. William Dahut's words, "usually preventable and treatable when caught early."

Dahut is the chief scientific officer at the American Cancer Society. He said adding a new option could "dramatically increase" the number of people who get screened.

That's the argument for the blood test in one sentence: some people won't do a colonoscopy, won't collect a stool sample, and will continue doing nothing. A simple blood draw might actually get them screened.

The Real Catch

Here's where the coverage gets soft.

The Shield test is 83% effective at finding colorectal cancers — according to NBC News. Sounds solid. But that number comes with a serious asterisk.

The test is significantly less effective at catching precancerous polyps and early-stage disease. Why? Because precancerous polyps don't shed DNA into the blood. The test only picks up what tumors are already releasing — meaning it's better at finding cancer that's already progressed.

Dr. Scott Kopetz, a gastrointestinal oncologist at the University of Texas MD Anderson Cancer Center, told NBC News he and his colleagues are "generally enthusiastic" about more options — but flagged a real concern: people might treat this blood test as equivalent to a colonoscopy and skip the more effective screenings they could have gotten otherwise.

"The concern is that we're going to lose ground in our battle for colorectal cancer prevention and early detection," Kopetz said.

The concern isn't just about what the test misses. It's that offering an easier option might actually reduce the quality of screening for people who would have done something better.

What Media Coverage Is Leaving Out

All four sources reported this responsibly, but they underplayed two things worth saying loudly.

First: insurance coverage is NOT guaranteed. The ACS recommendation alone does NOT require insurers to cover Shield. Coverage typically follows a recommendation from the U.S. Preventive Services Task Force — a separate federal body that has NOT yet weighed in on this test. Without that, the Shield test costs $895 out of pocket, according to NBC News. For a test being marketed as the low-barrier option to reach underscreened Americans, that price tag is a problem. The people most likely to skip a colonoscopy are often the same people least likely to drop $895 cash.

Second: there's no long-term survival data yet. NBC News acknowledged this, but it deserves more emphasis. As of the guideline's release, there is no data proving the Shield test actually reduces colorectal cancer deaths over time. The ACS is recommending a test that works in lab terms but hasn't proven its ultimate purpose in population terms. That's a reasonable gamble, given the screening gap — but it's a gamble, and patients deserve to know that.

Who This Test Is Actually For

The ACS guidelines are explicit: the blood test is recommended only for people who can't or won't undergo more effective screenings — colonoscopies or stool tests. It is NOT meant to replace those options.

A colonoscopy remains the gold standard. It lets doctors see inside the colon directly, find and remove precancerous polyps on the spot, and prevent cancer before it starts. No blood test does that.

The stool-based tests, while less convenient, also outperform Shield on early detection.

The Verdict

This is genuinely good news — with conditions. A third of Americans aren't getting screened for a cancer that's increasingly killing people in their 30s and 40s. If a blood test closes that gap even partially, lives get saved.

What this actually is: a fallback option for people who won't do better. Not a revolution in cancer screening. Not a replacement for a colonoscopy. And currently, an $895 out-of-pocket expense with no federal insurance mandate attached.

If you're eligible, get screened. The best test is the one you'll actually do. But if you can do a colonoscopy, do the colonoscopy.