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CION Cancer Clinics
FIT test explained: what the home stool test can and cannot tell you | CION Cancer Clinics
A FIT, or faecal immunochemical test, checks a small stool sample for blood too faint to see. It is a screening test for adults who feel well, not a test for cancer. A positive result means you need a colonoscopy to find where the blood came from. This page explains how the test works, who it suits, who should skip it, and what each result really means. At CION Cancer Clinics, our specialists help you judge which bowel symptoms need tests and plan screening that fits your risk.
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Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed October 2026, next review due October 2027
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The short answer
What is a FIT test, and what does it look for?
A FIT, or faecal immunochemical test, is a home stool test that looks for tiny amounts of human blood you cannot see. It is a screening test for people who feel well. A positive result means you need a colonoscopy to find where the blood came from. It never tells you that you have cancer.
How the test works
The kit is a small tube with a grooved stick in the cap. You scrape a little stool onto the stick, seal it and return the tube to a laboratory. There, an antibody that reacts only to human haemoglobin, the red protein in blood, checks the sample. Because it ignores blood from meat and iron from food, you do not need to change your diet first. The practical steps for taking the sample have their own page.
Why hidden blood matters
Some polyps, the small growths that can slowly turn into cancer, and many early colon cancers bleed slightly into the bowel. The amounts are far too small to colour the stool. Finding that blood gives a doctor a reason to look inside the colon before any symptom appears.
What it is good at, and what it misses
A FIT is better at picking up cancers than polyps, because cancers bleed more often. Many small polyps do not bleed at all, so they slip past. Bleeding also comes and goes. That is why one clear result is not a promise, and why the test is repeated on a schedule.
A FIT sorts people into two groups: look closer, or carry on screening. The looking closer is done by colonoscopy.Is it the right test for you?
Who is a FIT meant for, and who should skip it?
A FIT is built for one group: adults at average risk with no bowel symptoms. Everyone else needs a different route.
Adults at average risk
No symptoms, no close relative with colon cancer and no long-standing bowel disease. For this group, a FIT repeated on schedule is a reasonable way to screen. Most international guidelines now begin in the mid-forties to fifty.
People not ready for a colonoscopy
Some people cannot take a day off, live far from a hospital, or are simply not ready for a camera test. A FIT done regularly is far better than no screening at all, and it can be done in a village as easily as in Hyderabad.
Not for anyone with symptoms
Symptoms need a doctor, not a home kit. A negative FIT does not cancel any of these, and waiting for one delays the test you need.
See a doctor instead if you have
- Blood you can see in or on the stool
- A change in bowel habit that lasts
- Weight loss without trying
- Anaemia, a low haemoglobin, with no clear reason
Not for higher-risk families
These groups usually go straight to colonoscopy, on a schedule a doctor sets, often starting younger.
- A parent, brother or sister with colon cancer
- Lynch syndrome or a polyposis syndrome in the family
- Ulcerative colitis or Crohn's disease for many years
- Several polyps removed in the past
Not sure whether this applies to you?
Ask an oncologistFrom kit to next step
What happens after you send the sample?
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You collect one small sample at home
Kits come from a doctor or a diagnostic laboratory. You take one sample, seal it and return it as quickly as the leaflet asks, because the blood in the tube slowly breaks down.
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The lab measures the blood
Some labs simply report positive or negative. Others give a number and compare it with their own cut-off, the level above which the result counts as positive.
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Negative: carry on screening
No blood above the cut-off was found. You repeat the test on the schedule your doctor follows. If symptoms appear in between, you see a doctor without waiting for the next kit.
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Positive: a colonoscopy comes next
Blood was found. The next step is a colonoscopy, a camera test that looks along the whole colon and can remove polyps in the same sitting. CION arranges it at an accredited partner hospital.
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The colonoscopy gives the real answer
Most people with a positive FIT do not have cancer. The camera may find piles, a polyp that is removed on the spot, inflammation, or nothing at all. Only a biopsy, a small piece of tissue checked under a microscope, can diagnose cancer.
Side by side
How does a FIT compare with a colonoscopy?
FIT
Colonoscopy
Done at home, in private
Done at a hospital, usually with sedation
No diet change or bowel preparation
Needs a bowel-clearing drink the day before
Looks for hidden blood only
Looks directly at the whole colon lining
Cannot remove anything
Can remove polyps during the test
Repeated every year or two
Repeated far less often if the colon is clear
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Commonly believed
Four things people believe about the FIT
"The stool test in my health check package was a FIT."
Often it was not. Many packages include a routine stool examination or the older guaiac occult blood test, which are different tests. Look on the report for the words immunochemical or FIT, and read what health check packages usually include.
"If I cannot see blood, there is nothing for a FIT to find."
That is exactly what the test is for. The blood it detects is invisible. Polyps and early cancers usually cause no symptoms at all, so feeling well says nothing about the lining of the colon.
"My piles explain the positive result, so I can ignore it."
Piles can cause a positive FIT, but nobody can tell that from the result alone. Many people have piles and a polyp at the same time. A colonoscopy is the only way to know where the blood came from, and doctors do not assume.
"A CEA blood test would be easier and does the same job."
It does not. CEA is a marker used to follow people already treated for colon cancer. It is often normal in early cancer and can be raised in smokers, so CEA is not a screening test.
Being straight with you
What this page cannot tell you
It cannot tell you whether you have polyps or cancer, and neither can a FIT. The test answers one narrow question about one sample. A colonoscopy, arranged by a doctor, is what answers the bigger one.
It cannot choose your screening test for you
Whether a FIT or a colonoscopy suits you depends on your age, your family history, your health and what you will realistically keep doing. In India, bowel screening is mostly something you ask for rather than something you are invited to, so that conversation is worth having. A CION oncologist can talk it through and arrange either test through a partner.
Who this does not apply to
This page is about screening people who feel well. If you have symptoms, a strong family history, a known gene fault, or long-standing inflammatory bowel disease, the FIT pathway is not yours. The high-risk screening pathway explains the route you need instead.
Unsure which group you are in? Call the helpline, describe your history, and someone will tell you plainly which test fits.Questions we are asked
Common questions about the FIT test
Is a FIT a test for cancer?
No. It is a test for hidden blood in the stool. That blood can come from piles, a small tear, inflammation, a polyp or a cancer, and the FIT cannot tell which. A positive result means you need a colonoscopy. Only a colonoscopy with a biopsy can diagnose cancer.
How is a FIT different from the older stool blood test?
The older guaiac test reacts to any blood, including blood from red meat, and some foods and medicines confuse it. It needed a diet change and several samples. A FIT reacts only to human blood and usually needs a single sample, which is why far more people complete it.
How often should a FIT be repeated?
It depends on the guideline your doctor follows. American guidance repeats it every year, and the UK programme every two years. What matters most is that it is repeated. A single clear result covers only a short window, because polyps and cancers do not bleed every day.
At what age should I start?
Most international guidelines start screening average-risk adults somewhere between the mid-forties and fifty. If a parent or sibling had colon cancer, screening usually starts earlier and the test is usually colonoscopy. Ask a doctor which applies to you before relying on a FIT.
Can a FIT be used if I already have symptoms?
In the UK, family doctors sometimes use a FIT that gives a number to decide how quickly someone with symptoms needs a colonoscopy. That is a doctor's decision, made alongside an examination. A negative FIT on its own never rules out cancer when you have symptoms, so see a doctor first.
What does a positive FIT result mean?
Blood was found above the laboratory's cut-off. It does not mean cancer, and most people with a positive result do not have it. The next step is a colonoscopy, not a repeat FIT. What happens after a positive FIT explains the weeks ahead.
Do aspirin or blood thinners affect the result?
They can make a small bleed, from piles for example, more likely to show up. That may lead to a colonoscopy that finds nothing serious. Do not stop them for the test. Tell the doctor who reads your result exactly which medicines you take.
Can I get a FIT in Hyderabad, and what does it cost?
Most large diagnostic laboratories in Hyderabad offer it, and some collect samples from home. Ask for the immunochemical test by name. Prices vary between laboratories, and it is one of the cheaper screening options. CION can arrange a kit through a diagnostic partner if you prefer.
Your Specialists
Meet CION's colon cancer specialists. Bring your colonoscopy, scan or biopsy report.
Our surgical and medical oncologists plan colon cancer care together: which operation, whether chemotherapy is needed, and the follow-up that comes after.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
Surgical Oncologist
Dr. Muralidhar Muddusetty
MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)
Surgical Oncologist
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Sources
- National Cancer Institute — Screening Tests to Detect Colorectal Cancer and Polyps
- American Cancer Society — Colorectal Cancer Screening Tests
- NHS — Bowel cancer screening
- NICE — Quantitative faecal immunochemical testing to guide colorectal cancer pathway referral in primary care
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
How to Do a FIT Test at HomeStep-by-step help taking the sample without spoiling itA Negative FIT Result: What It Does Not Rule OutWhy a clear result does not cancel a symptomFOBT vs FIT: Which Is Better?If your lab offers the older guaiac test insteadScreening Options ComparedHow a FIT stacks up against colonoscopy and the other tests
Talk to us
Not sure whether a FIT is the right test for you?
Tell us your age, your family history and any symptoms. We will tell you plainly which screening test fits and arrange it through a partner if you want. One helpline serves every CION centre.