Blood-based colorectal cancer screening is scaling fast, and a second FDA-approved test launched Sept. 30. For GI ASCs, the question is whether those tests feed colonoscopy volume or replace it.
The market is growing
Guardant Health performed about 66,000 Shield tests in the second quarter of 2026, up from about 16,000 a year earlier, according to the company. Screening revenue reached $52.9 million for the quarter. Guardant raised its 2026 forecast to 270,000 to 285,000 Shield tests, up from 230,000 to 245,000.
UnitedHealth Group became the first major commercial insurer to cover Shield, the company said.
On July 24, the FDA approved Freenome’s SimpleScreen CRC, the second blood test cleared for average-risk adults 45 and older, according to the American Gastroenterological Association. Abbott, which holds exclusive U.S. rights, launched the test Sept. 30, according to the company. Medicare covers the test, and eligible Part B patients pay nothing out of pocket. Medicare Advantage patients may face cost-sharing, Abbott said. Abbott also sells the Cologuard Plus stool test.
The guidelines still favor colonoscopy
The American Cancer Society added a blood test to its screening guidelines on May 27 but kept colonoscopy as the primary recommendation, according to the American Hospital Association. ACS recommends blood tests only for people who decline or do not complete preferred screening.
The AGA said in June that blood tests “should be approached with caution.”
The performance gap is in precancerous lesions. SimpleScreen detected 81.1% of colorectal cancers but 13.7% of advanced precancerous lesions in the weighted analysis of the PREEMPT CRC trial, according to HCPLive.
Where colonoscopy volume is at risk
The threat to GI ASCs comes from two directions.
- Substitution. Patients who choose a blood test instead of colonoscopy leave the ASC schedule, and the clinical trade-off is steep. A 2024 Stanford Medicine-led model in the Annals of Internal Medicine projected about 1,600 to 1,680 colorectal cancer deaths per 100,000 people screened with blood tests every three years, vs. 672 with colonoscopy every 10 years, according to Stanford Medicine.
- Lost follow-up. A positive blood test requires a diagnostic colonoscopy. A UCLA study of 6,068 patients who received Shield from 2022 to 2024 found 7.4% had abnormal results. Only 49% of those with at least six months of follow-up got a colonoscopy within six months, and 56% got one at any point, according to Inside Precision Medicine. Medicare Advantage patients were 74% less likely than privately insured patients to follow up within six months after adjusting for other factors, the outlet reported.
“Blood-based colorectal cancer screening is promising, but it only works if individuals complete the follow-up colonoscopy,” said Folasade May, MD, the study’s senior author.
There is also an upside. About 1 in 3 U.S. adults in the screening age range have never been screened, according to Stanford Medicine. If blood tests reach those patients and positives are routed to colonoscopy, they add volume rather than remove it.
“The most effective screening test is the one a person will actually complete,” said Aasma Shaukat, MD, co-lead principal investigator of PREEMPT CRC, according to HCPLive.
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