Screening & monitoring · graded by use, three uses
FIT Test (Fecal Immunochemical Test)
Colorectal cancer mortality, guaiac FOBT (gFOBT).
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How this letter has changedLatest: October 2026 · Downgraded.
The use held B on COLONPREV alone (Castells et al., Lancet, 2025; PMID PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed. 40158525), with its second citation the same trial's baseline report (PMID 22356323), and the review of October owed a replication The same finding reproduced by a separate research group. A result seen once can be chance or bias; a replicated one is harder to explain away. search. The search found none: CONFIRM (Dominitz et al., Am J Gastroenterol, 2017; PMID 29016565) has published only its design, and SCREESCO (Westerberg et al., Nat Med, 2026; PMID 41721101) compares each test with usual care and reports incidence, not mortality. A single trial nobody has repeated is C. The gFOBT A and the FIT-specific D Route 1 No human randomized trial has been run, so the record rests on animal or mechanistic evidence only. One of the two routes to the lowest letter on EBL's scale. are unchanged. Applied the written grade definition under the editor's standing instruction of October 2026 (Arnold Sandlow, D.C.).PMID 22356323 PMID 29016565 PMID 40158525 PMID 41721101
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These are home stool tests that look for hidden blood as an early sign of colon cancer. With the older card test, called guaiac testing, large trials in the US, the UK and Denmark found fewer deaths from colon cancer. Those programs sent people with a positive test on to a colonoscopy. The newer test most people get today, called FIT, has no trial showing it cuts colon cancer deaths. One large trial found FIT about as good as a single colonoscopy. Neither test lowered deaths from all causes. The colonoscopy after a positive result carries a small risk of a tear or bleeding.
The A belongs to one of the three uses graded on this record. The other two carry their own letters.
As studied, and the trials
Randomized, replicated, on a hard clinical endpoint The outcome a trial measures to decide whether the treatment worked, such as heart attacks, blood pressure or a symptom score.. Shaukat et al. (New England Journal of Medicine, 2013; PMID 24047060), the 30-year Minnesota follow-up, reported a 32 percent reduction in colorectal-cancer mortality with guaiac FOBT. Kaneko et al. (Therapeutic Advances in Gastroenterology, 2026; PMID 42254696), a network meta-analysis A study that pools the numbers from several trials into one combined estimate. of nine randomized trials, found gFOBT reduced colorectal-cancer mortality on intention to treat, RR 0.87 (95% CI 0.79 to 0.95). Neither found a reduction in all-cause mortality.
As studied, and the trials
This letter is about the evidence, not about the test. FIT detects human hemoglobin specifically and outperforms guaiac FOBT on sensitivity and specificity, and it is the stool test in routine use. What is missing is randomized evidence that FIT itself reduces colorectal-cancer mortality. Kaneko et al. (Therapeutic Advances in Gastroenterology, 2026; PMID 42254696) found the reduction for flexible sigmoidoscopy and for guaiac FOBT and not for FIT, and described the FIT evidence as limited. Doubeni et al. (JAMA Network Open, 2024; PMID 39028667), the FIT-specific study EBL cites, is a nested case-control design, not a randomized trial. Grade D here means the randomized evidence for this test on this endpoint has not been produced. It is not a finding that FIT failed.
As studied, and the trials
Castells et al. (Lancet, 2025; PMID 40158525), COLONPREV: a pragmatic randomized non-inferiority trial in 57,404 adults aged 50 to 69. Invitation to biennial FIT was non-inferior to invitation to one-time colonoscopy for colorectal-cancer mortality at 10 years, 60 deaths against 55, risk difference -0.02 percent (95% CI -0.10 to 0.06). Participation was higher in the FIT arm. A single trial that no one has repeated is C under the written rule, however large; it was held at B until the replication search of October 2026 confirmed that no second trial has reported. It answers a different question from the row above: non-inferior to colonoscopy is not the same claim as reduces mortality against no screening, and this trial had no unscreened arm. Quintero et al. (New England Journal of Medicine, 2012; PMID 22356323) is the same trial's baseline report, before the mortality endpoint matured.
Read the grade that matches your goal. How EBL grades by use →
Cancer screening · Colorectal health
A letter describes the human evidence, not the product, the manufacturer, or the intervention's worth.
Why this gradeThe reasoning, and what the grade does not cover.
Grade A by the hard-outcome route: colorectal-cancer mortality in a randomized screening trial with thirty years of follow-up, plus a network meta-analysis of nine randomized trials.
WHAT THIS GRADE DOES NOT COVER, AND THIS IS THE WHOLE POINT OF GRADING BY TESTthe randomized mortality evidence is for GUAIAC FOBT. The test most people are actually handed is FIT, and on intention to treat FIT did not reduce colorectal-cancer mortality in that same analysis, with its evidence described as limited. FIT therefore sits at D on this record and the A does not transfer to it on the strength of a shared detection principle. Neither test reduced all-cause mortality in any strategy. And non-inferiority against colonoscopy, which is graded separately at C as a single unreplicated trial, is not evidence of a reduction against no screening at all.
Shared endpoint: Colorectal-cancer mortality with guaiac fecal occult blood screening versus no screening
- Minnesota Colon Cancer Control Study, USA (Shaukat): 32 percent lower colorectal-cancer mortality at 30 years with annual screening. PMID 24047060 · Funding: academic
- Nottingham, UK (Hardcastle): 15 percent lower colorectal-cancer mortality, 152,850 people. PMID 8942775 · Funding: academic
- Funen, Denmark (Kronborg): Colorectal-cancer mortality ratio 0.82, 61,933 people, 10 years. PMID 8942774 · Funding: academic
What the replication does not cover: The replicated mortality evidence is for guaiac FOBT, not FIT.
A grade describes the human evidence for a named use. It is not advice, and it is not a judgment on any individual prescription. How the letters are decided →
The fecal immunochemical test is an at-home colorectal cancer screening test. EBL grades this record by use, because the randomized mortality evidence and the test most people actually use are not the same thing. The 30-year Minnesota result belongs to guaiac FOBT. For FIT itself, no randomized trial has shown a mortality reduction against no screening, and one randomized trial has shown it non-inferior to colonoscopy. Colorectal cancer is the second leading cause of cancer death in the US. The randomized mortality reductions of 21 to 32 percent come from guaiac FOBT in the Minnesota trial, not from FIT. It costs $20 to $70, takes 5 minutes, and requires no bowel prep, no dietary restriction, and no prescription.
| How it works | Detects occult (hidden) human blood in stool using antibodies specific to human hemoglobin. Unlike the older guaiac test, FIT is not affected by diet, aspirin, or vitamin C. Positive result triggers diagnostic colonoscopy. |
| Product availability | Polymedco OC FIT-CHEK is one of several FIT products in routine use. EBL does not grade FIT brands against each other and holds no evidence that would support ranking them. Available through IHDLab (ihdlab.com) direct-to-consumer. |
| Consumer cost | $20 to $70 depending on provider. IHDLab: approximately $35 including lab processing. Amazon: $15-25 for qualitative home kits (no lab required). Insurance: covered at no cost for adults 45+ by most plans under ACA preventive care mandate. |
| Wholesale (practitioner) | $0.83 to $6.41 per test from medical distributors. Insurance reimbursement $21.55 on CPT code G0328QW / 82274QW. Pinnacle BioLabs sells 20-pack kits for office use. |
| Population studied | The USPSTF recommends colorectal cancer screening for average-risk adults aged 45 to 75, an A recommendation from 50 to 75 and a B recommendation from 45 to 49. Annual FIT is one of several recommended strategies, alongside colonoscopy, CT colonography, flexible sigmoidoscopy and other stool-based tests; the task force does not tier them. From 76 to 85 the decision is individualised on overall health, prior screening history and preference, a C recommendation. The average-risk definition excludes prior colorectal cancer, adenomatous polyps, inflammatory bowel disease and the hereditary syndromes, all of which follow different schedules. The USPSTF makes no separate recommendation by race, and states that the evidence does not support one; its 2021 statement lowered the start age to 45 for all average-risk adults. |
| Positive result | Requires diagnostic colonoscopy. A positive FIT does not mean cancer. Most positive FITs are from benign causes (polyps, hemorrhoids, benign ulcers). Colonoscopy both diagnoses and removes precancerous polyps. |
Annual test from age 45. A useful record holds the test date, the result (positive or negative), and any follow-up colonoscopy findings and dates. A negative FIT is reassuring for that year but does not replace the next annual test. It sits on the EBL longevity lab panel as an annual screening marker.
30-year follow-up of the Minnesota Colon Cancer Control Study, the longest randomized screening trial of its kind. It tested GUAIAC FOBT, not FIT. Annual testing reduced colorectal cancer mortality by 32 percent compared to no screening. Biennial testing reduced mortality by 21 percent. This is the foundational evidence for annual FIT screening recommendations.
Invitation to biennial FIT was non-inferior to invitation to one-time colonoscopy for colorectal cancer mortality at 10 years, 60 deaths against 55, risk difference -0.02 percent (95% CI -0.10 to 0.06). Participation was higher in the FIT arm. There was no unscreened arm, so this does not show FIT reduces mortality against no screening. Colonoscopy has higher single-test sensitivity but FIT's annual frequency compensates for lower per-test sensitivity. Adherence to annual FIT is typically higher than colonoscopy compliance.
The baseline report of the trial above, before its mortality endpoint had matured. Detection rates for advanced neoplasms were similar between the two strategies at first screening, with FIT being significantly more acceptable to patients (adherence 34.2% vs 24.6% at 10 years in intention-to-treat Analyzing everyone in the group they were assigned to, even if they stopped the treatment, so the comparison stays randomized. analysis).
The test itself has no safety risks. A positive result requires diagnostic colonoscopy which carries a small procedural risk (perforation approximately 1 in 1,000, bleeding approximately 2 in 1,000). That procedural risk is part of the screening pathway the mortality trials tested.
NSAIDs, aspirin, and anticoagulants may cause gastrointestinal bleeding that produces a false positive FIT. If on these medications, inform your physician when interpreting a positive result. Vitamin C and dietary factors do not affect FIT (unlike the older guaiac FOBT test).
The FIT test sits on EBL's longevity lab panel. The Grade A on this record belongs to guaiac FOBT. FIT itself carries Grade D against no screening and Grade C non-inferior to colonoscopy, a single trial, and each letter is shown with its trial below. Polymedco FIT is available through IHDLab (ihdlab.com). Insurance covers it at no cost for most adults over 45. Whether to screen, and at what interval, is a decision for you and your physician.
Educational use only · Not medical advice · Starting, stopping or changing any supplement or medication is a decision for your physician
EBL does not verify the regulatory status of any device. Many consumer wellness devices are not FDA-cleared The FDA found a device substantially equivalent to one already on the market. Clearance is not approval and does not require trials showing benefit., and FDA clearance, where it exists, applies only to specific indications. The grade on this page describes the strength of published human trial evidence in the populations studied. It is not a recommendation for any individual and is not medical advice. Using any device for a health purpose is a decision for your physician.
Primary evidenceFour papers, each linked to its PubMed record.
Graded by test, because the randomized mortality evidence and the test most people actually use are not the same thing. Shaukat et al. (New England Journal of Medicine, 2013; PMID 24047060): 30-year follow-up of the Minnesota randomized screening trial, colorectal-cancer mortality reduced by 32 percent, using GUAIAC FOBT. Kaneko et al. (Therapeutic Advances in Gastroenterology, 2026; PMID 42254696): systematic review A review that searches for every study on a question using a method set in advance, then assesses them together. and network meta-analysis of nine randomized trials at about 10 years. On intention to treat, gFOBT reduced colorectal-cancer mortality (RR 0.87, 95% CI 0.79 to 0.95) and FIT did not, with the FIT evidence described as limited. No strategy reduced all-cause mortality. Doubeni et al. (JAMA Network Open, 2024; PMID 39028667) is the FIT-specific evidence EBL cites and it is a nested case-control study, not a randomized trial. The Grade A therefore belongs to gFOBT and to stool-based screening as a strategy. It does not transfer to FIT on the strength of a shared detection principle. Castells et al. (Lancet, 2025; PMID 40158525) reported COLONPREV's 10-year mortality endpoint: FIT was non-inferior to colonoscopy, which is graded separately below at C, a single trial. Non-inferiority against an active comparator is not evidence of a reduction against no screening.
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How EBL searched for the trials (1 search)
The search that was run, what it returned, and what was left out and why, so the absence of evidence can be checked as well as its presence.
(fecal immunochemical test[tiab] OR FIT[tiab]) AND colonoscopy[tiab] AND (mortality[tiab] OR incidence[tiab]) AND randomized controlled trial[pt] AND (colorectal cancer[tiab])Grades move when new trials publish. A free monthly email lists every grade EBL moved, with the reason and the trial behind it: the sign-up is on the Evidence Log →