Stool for Occult Blood Test

A stool occult blood test is a simple, non-invasive screening that checks for hidden blood in your digestive tract. It is commonly used to detect early signs of colorectal cancer or other sources of gastrointestinal bleeding. The test is often recommended for adults over age 45 (or earlier if you have a family history of colorectal cancer) and for people with unexplained anemia or symptoms like chronic abdominal pain. A positive result does not mean you have cancer—it simply signals that more investigation is needed.

What is a stool occult blood test?

The term “occult” means hidden. This test looks for tiny amounts of blood in your stool that are not visible to the naked eye. There are two main types:

• Guaiac-based FOBT (gFOBT): Uses a chemical reaction to detect heme (a component of hemoglobin). Requires dietary restrictions.
• Fecal immunochemical test (FIT): Uses antibodies to detect human hemoglobin. More specific and usually does not require dietary changes. Many urban labs in Bangladesh (e.g., Popular, Medinova) now offer FIT.

Both are used for colorectal cancer screening.

Why is this test ordered?

Common reasons include:

• Colorectal cancer screening for individuals aged 45–75 (the Bangladesh Society of Gastroenterology recommends starting at age 45, or earlier for those with a family history).
• Unexplained iron-deficiency anemia (blood loss from the GI tract can cause anemia).
• Suspected gastrointestinal bleeding from ulcers, polyps, hemorrhoids, or inflammatory bowel disease.
• Follow-up after a previous positive FOBT (to monitor after treatment).

It is a screening test, not a diagnostic one. A positive result requires further investigation.

How to prepare for the test

Preparation depends on the type of test.

For guaiac-based FOBT:

Avoid the following for 2–3 days before sample collection:

• Red meat (beef, lamb, pork)
• Certain raw vegetables like broccoli, turnips, horseradish, and cantaloupe
• Vitamin C supplements and foods high in vitamin C (citrus fruits)
• NSAIDs (ibuprofen, naproxen, aspirin) — these can cause bleeding
• Alcohol

For FIT:

Usually no dietary restrictions are needed. You may continue eating normally. However, ask your doctor about any medications you take.

Always follow the specific instructions provided by your laboratory.

How is the sample collected?

Collection is done at home using a kit provided by the lab. Steps:

1. Obtain the collection container and applicator stick from the lab.
2. Collect a small sample from the stool (about the size of a pea) using the stick.
3. Avoid mixing the sample with urine or toilet water.
4. Place the sample in the container, seal it, and label with your name and date.
5. Return the sample to the lab as soon as possible (within 24 hours if possible).

Results typically take 1–3 days.

What do the results mean?

Negative result: No occult blood detected. This is reassuring but does not guarantee the absence of disease. Screening should be repeated at the intervals your doctor recommends.

Positive result: Blood was detected in the stool. This does not mean you have cancer. Many benign conditions can cause bleeding: hemorrhoids, anal fissures, polyps, diverticulosis, or inflammation. However, a colonoscopy is needed to identify the source.

False positives can occur if dietary restrictions were not followed for guaiac-based tests. False negatives can occur if bleeding is intermittent or the test is done incorrectly.

Always discuss your results with a qualified clinician.

Follow-up after a positive result

If your test is positive, the next step is usually a colonoscopy. This allows the doctor to examine the entire colon and remove any polyps or take biopsies. Most positive results turn out to be benign, but prompt follow-up is important to rule out cancer or treat the source of bleeding.

It may be helpful to consult a gastroenterologist or an oncologist for further guidance. Use the table below to find oncologist specialists across Bangladesh.

Cost of the test in Bangladesh

Prices vary by city, lab quality, and test type. The ranges below are approximate and may change; always confirm with the lab before booking.

Some labs may bundle the test with a doctor’s consultation or offer it as part of a health package. Costs in major hospitals (e.g., Apollo, Square) may be higher. Ask your healthcare provider for a reference.

Also see the comparison table below for key differences between the two methods.

Prices and availability may change. Confirm with your chosen lab.

Frequently Asked Questions

What foods or medicines should I avoid before a stool occult blood test?

Many test kits require you to avoid red meat, raw fruits and vegetables (especially broccoli, turnips, and horseradish), and vitamin C supplements or citrus fruits for 3 days before collecting the sample. Certain medications—such as aspirin, ibuprofen, iron supplements, and blood thinners—can also cause false positives. Always check the specific instructions provided with your test kit, and do not stop any prescribed medicine without consulting your doctor first.

Can hemorrhoids or anal fissures cause a false positive result?

Yes. Bleeding from hemorrhoids, fissures, or during a heavy menstrual period can contaminate the stool sample and produce a positive result that is not related to colon polyps or cancer. To avoid this, your doctor may advise you to collect the sample when you are not actively bleeding from these conditions, or to use a different preparation method. Inform your physician of any known bleeding sources before the test.

Sources

The following sources are from international journals, government health agencies, or recognized medical organizations:

• World Health Organization — Stool for Occult Blood Test (who.int)
• MedlinePlus — Stool for Occult Blood Test (medlineplus.gov)
• CDC — Stool for Occult Blood Test (cdc.gov)
• NHS — Stool for Occult Blood Test (nhs.uk)
• PubMed — Stool for Occult Blood Test (pubmed.ncbi.nlm.nih.gov)
• Mayo Clinic — Stool for Occult Blood Test (mayoclinic.org)