Header: CMS is reviewing its coverage standards for CRC screening biomarkers - stool, blood, etc. But CMS explicitly will ignore fitting FIT testing into the new system. (FIT testing will remain untouched and as-is.)
There's quite a story there - FIT testing is FDA-regulated much differently than Cologuard, Reveal, etc. Here's an essay planned by me, but written by Chat GPT 4 in a few seconds.
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FIT Testing: Why It Has a Special, Hands-Off Status in the Screening NCD
Chat GPT 5.4
CMS’s current proposal on non-invasive colorectal cancer biomarker tests is notable not only for what it addresses, but also for what it leaves untouched. CMS is proposing new evidence standards for emerging biomarker tests, but it is not reopening its longstanding coverage of FIT and guaiac FOBT under the colorectal cancer screening benefit. That omission is interesting—at least to CMS policy nerds—because FIT looks simple from a distance but becomes surprisingly complicated if one tries to revisit the benefit rigorously. CMS may have decided it is better not to stir that particular hornet’s nest. [1][2]
The key issue is regulatory. FIT is not regulated like Cologuard.
Cologuard and newer blood-based screening tests carry explicit colorectal cancer screening claims and went through the PMA pathway. FIT generally sits in a much older regulatory box: 21 CFR 864.6550 (occult blood test), a Class II device usually cleared through 510(k). In FDA terms, most FIT products are cleared simply to detect human hemoglobin in stool, i.e., occult blood. That is analytically narrower than a claim to screen asymptomatic adults for colorectal cancer, and historically easier to support in a 510(k) submission. [3][4][5]
The situation is not perfectly uniform, however. Some FIT products include more explicit screening language in their labeling.
A commonly cited example is OC-FIT-CHEK, whose intended use includes detection of human hemoglobin as an aid in identifying colorectal cancer or adenomas in asymptomatic adults undergoing screening. So the precise statement is that most FITs are cleared as occult blood tests, while a few include screening-oriented language. Even this small labeling variation hints at the complexity CMS would face if it tried to revisit the FIT benefit across all currently available FIT products. [6]
Meanwhile, Medicare coverage treats FIT squarely as a screening tool. The existing colorectal cancer screening NCD covers annual FOBT and specifies that this can be either guaiac FOBT or FIT (iFOBT). CMS coverage policy therefore recognizes FIT as part of the screening benefit even though the FDA device labeling for many FIT products focuses on occult blood detection rather than an explicit cancer screening claim. Clinical guidelines reinforce the same practice pattern by recommending annual FIT as a screening option alongside colonoscopy and other strategies. [2][7]
The result is an interesting two-layer regulatory structure. FDA regulates the assay and its labeling, while guidelines and CMS policy define how the test functions in population screening.
For FIT, the FDA label is often narrower than the role the test plays in screening programs. Over time, however, repeated annual testing, epidemiologic evidence, and guideline adoption made FIT a standard screening modality regardless of these labeling nuances. [2][3][7]
Reopening the FIT benefit would therefore be far from straightforward. There are many FIT brands, different collection devices and analyzers, and different positivity thresholds, which move sensitivity and specificity in opposite directions. Published performance varies widely depending on study design, endpoints (cancer vs. advanced adenoma), and screening round. CMS is currently proposing clearer performance expectations for new biomarker tests; applying that same scrutiny retrospectively to FIT would mean sorting through decades of heterogeneous evidence and device labeling across an entire product class already embedded in Medicare’s preventive benefit. [1][2]
There is also a pragmatic policy reason for restraint. FIT is the incumbent technology—cheap, familiar, guideline-endorsed, and already integrated into clinical practice. By contrast, newer stool RNA, DNA, or blood-based biomarkers arrive asking CMS to define new evidentiary thresholds for coverage. It is much simpler for CMS to clarify standards for these new entrants than to reopen the long-settled FIT category and revisit questions about comparative evidence, labeling differences, or test-specific performance.
So the takeaway is a mildly paradoxical one. At the FDA level, most FIT tests are cleared as occult blood assays rather than formal colorectal cancer screening devices. At the Medicare and guideline level, FIT has long been treated as a bona fide screening strategy. That mismatch is historically contingent but stable. Reopening it might be theoretically appealing, but it would quickly lead CMS into a complicated review of heterogeneous devices, decades of studies, and entrenched clinical practice. For now, leaving FIT alone while tightening standards for newer biomarkers is not only administratively easier—it is probably the most rational policy choice.
Sources
[1] CMS, Proposed Decision Memo, Screening for Colorectal Cancer—Non-Invasive Biomarker Tests (CAG-00440R)
https://www.cms.gov/medicare-coverage-database/view/ncacal-decision-memo.aspx?NCAId=319&proposed=Y
[2] CMS, National Coverage Determination 210.3, Colorectal Cancer Screening Tests
https://www.cms.gov/medicare-coverage-database/view/ncd.aspx?NCDId=281
[3] Electronic Code of Federal Regulations, 21 CFR 864.6550 – Occult blood test
https://www.ecfr.gov/current/title-21/chapter-I/subchapter-H/part-864/subpart-G/section-864.6550
[4] FDA Product Classification Database, Occult blood test / Product code KHE
https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpcd/classification.cfm?panel=HE®ulationnumber=864.6550
[5] FDA 510(k) review example for a FIT device (OC-Light FIT)
https://www.accessdata.fda.gov/cdrh_docs/reviews/K143325.pdf
[6] FDA 510(k) database entries for FIT products including OC-FIT-CHEK
https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm
[7] FDA Consumer Update, Colorectal Cancer: What You Should Know About Screening
https://www.fda.gov/consumers/consumer-updates/colorectal-cancer-what-you-should-know-about-screening
