The Food and Drug Administration has approved a second blood test for colorectal cancer screening, giving adults who avoid colonoscopy and stool tests another option and giving clinicians another conversation to have about what that option does and does not find.
Freenome's SimpleScreen CRC, approved July 27, joins Guardant Health's Shield, approved in 2024. Both are indicated for adults aged 45 and older at average risk who have been referred for screening. MedTech Dive reported that Abbott will exclusively market SimpleScreen in the United States starting this fall, alongside the Cologuard stool test it acquired through its purchase of Exact Sciences earlier this year.
The clinical trade-off is the part worth understanding before you ask for one. Blood tests detect established colorectal cancer reasonably well. They detect the precancerous growths that colonoscopy removes far less well, and that gap is precisely why screening guidelines rank them below colonoscopy and stool tests rather than alongside them.
The Performance Numbers Behind the Approval
SimpleScreen was evaluated in PREEMPT CRC, which enrolled nearly 49,000 asymptomatic average-risk adults aged 45 to 85 across more than 200 sites, all scheduled for a screening colonoscopy. In a prespecified analysis adjusted to match the US Census, the test detected colorectal cancer with 81.1% sensitivity and advanced precancerous lesions with 13.7% sensitivity, rising to 30.7% for those lesions with high-grade dysplasia. Specificity for advanced colorectal neoplasia was 90.4%.
In practical terms, the test correctly detected about 8 in 10 colorectal cancers and returned negative results for about 9 in 10 people without cancer or advanced precancerous lesions.
The published primary analysis is worth reading alongside the marketing figures. In the peer-reviewed JAMA paper, sensitivity for colorectal cancer was 79.2% and specificity for advanced colorectal neoplasia was 91.5%, while sensitivity for advanced precancerous lesions was 12.5% and did not meet the prespecified acceptance criterion the investigators had set.
Shield's numbers are similar in shape. In the ECLIPSE trial published in the New England Journal of Medicine, Shield showed 83% sensitivity for colorectal cancer, about 90% specificity for advanced neoplasia, and 13.2% sensitivity for advanced precancerous lesions.
That last category is the one that matters most for how these tests are positioned. Advanced precancerous lesions include large adenomas and sessile serrated lesions, the growths that can become cancer over years and that a colonoscopist can remove during the same procedure. A test that misses roughly seven of every eight of them is a cancer-detection tool rather than a cancer-prevention tool.
Where the Guidelines Place These Tests
The American Cancer Society added blood-based tests to its colorectal screening guideline, but with a condition attached rather than as an equal option.
Colonoscopy and stool-based tests remain the preferred choices. Blood tests are recommended for patients who decline or do not complete a preferred test. The reasoning is stated in the guideline itself: blood-based tests showed lower sensitivity for both advanced precancerous lesions and stage I cancers, and modeling predicts they will be less effective at reducing colorectal cancer incidence and mortality.
The counterargument is adherence, and it is not trivial. Tens of millions of Americans are overdue for recommended colorectal screening. Aasma Shaukat of NYU Grossman School of Medicine, a co-lead principal investigator on PREEMPT CRC, made the case in one line: the most effective screening test is the one a person will actually complete.A test many people will finish may produce more benefit at the population level than a superior test many people skip. That is a genuine trade-off, not a marketing line, and it is why the guideline includes these tests at all.
With FDA approval, SimpleScreen meets Medicare coverage criteria and is expected to be added to the American Cancer Society guideline by name.
The Follow-Up Step People Underestimate
Any positive blood test result requires a follow-up colonoscopy. There is no version of this pathway that avoids colonoscopy if the result is abnormal, and the manufacturer states plainly that the test does not replace diagnostic or surveillance colonoscopy.
That has two practical consequences. First, a positive result on a screening blood test is not a diagnosis, and many positives will not turn out to be cancer. Second, the diagnostic colonoscopy that follows may be billed differently from a screening colonoscopy, which can mean out-of-pocket costs even for people whose plans cover screening at no cost sharing. Ask about this before testing, not after.
A negative blood test also carries a specific limitation. It does not rule out precancerous polyps, which is what a negative colonoscopy does for a decade. The screening interval for blood tests is considerably shorter, reflecting that weaker reassurance.
Deciding Which Test Fits Your Situation
Screening should begin at 45 for people at average risk. Colorectal cancer incidence has been rising among adults under 50, which is why the starting age moved down from 50. Among adults aged 45 to 49, only about one in five is current with recommended screening.
These blood tests are for average-risk adults only. They are not appropriate for people with a personal history of colorectal cancer or adenomas, inflammatory bowel disease, a family history of colorectal cancer, or genetic syndromes such as Lynch syndrome or familial adenomatous polyposis. Those groups need colonoscopy on a schedule set by a gastroenterologist.
They are also not for anyone with symptoms. Rectal bleeding, blood in stool, persistent change in bowel habits, unexplained iron deficiency anemia, unintended weight loss, or persistent abdominal pain require diagnostic evaluation, not a screening test. A negative screening result in someone with symptoms is a dangerous false reassurance.
If cost or access is the barrier rather than preference, ask about a fecal immunochemical test. FIT is inexpensive, done at home annually, and performs better than blood tests for advanced adenomas. Many health systems mail FIT kits at no cost, and community health centers and state colorectal cancer control programs can help uninsured patients access screening.
If the barrier is fear of the preparation or the procedure, say so directly to your clinician. That is the conversation these tests exist to open, and it is more productive than skipping screening entirely.
Frequently Asked Questions
What was approved? Freenome's SimpleScreen CRC, a blood test for colorectal cancer screening in average-risk adults 45 and older. It is the second such test after Guardant's Shield.
How well does it work? In the census-adjusted analysis, it detected colorectal cancer with 81.1% sensitivity and advanced precancerous lesions with 13.7% sensitivity, with 90.4% specificity for advanced neoplasia.
Why do guidelines rank blood tests below colonoscopy? Because they detect few advanced precancerous lesions, the growths colonoscopy can find and remove before they become cancer.
What happens if my result is positive? You will need a follow-up colonoscopy. Many positives will not turn out to be cancer, but the colonoscopy is required to determine that.
Will my insurance cover the follow-up colonoscopy? Coverage varies, and a diagnostic colonoscopy may be billed differently from a screening one. Ask your plan before testing.
Who should not use these tests? Anyone with symptoms, a personal or family history of colorectal cancer or adenomas, inflammatory bowel disease, or a genetic syndrome such as Lynch syndrome.
What is a lower-cost alternative? An annual fecal immunochemical test, which is inexpensive, done at home, and performs better than blood tests for advanced adenomas.
