Fecal Occult Blood (FOB) — Home Screening Test for Colorectal Cancer

Why fecal occult blood testing saves lives?

Colorectal cancer is the third most commonly diagnosed cancer worldwide and the second leading cause of cancer-related death in Europe. In Poland alone, approximately 18,000 new cases are diagnosed each year, with an overall five-year survival rate of only 50–60%.

The critical fact that makes screening so powerful is the timeline of this disease: colorectal cancer typically develops slowly over 10–15 years, progressing from a benign polyp through an adenomatous (precancerous) stage before becoming invasive. When caught at stage I or II, the five-year survival rate exceeds 90%. By contrast, detection at stage IV — when the cancer has metastasized — drops survival to below 15%.

The fecal occult blood test (FOB or FOBT) detects microscopic amounts of hemoglobin in stool that are invisible to the naked eye. Polyps and early-stage cancers often bleed in tiny quantities — too small to discolor the stool, but sufficient to be identified by a sensitive immunochemical test. Systematic FOB screening every one to two years has been shown in large clinical trials to reduce colorectal cancer mortality by 15–33%.

Who should take the FOB test?

European and Polish gastroenterological guidelines recommend regular colorectal cancer screening as follows:

General population (average risk): • From age 50 — FOB test every 1–2 years OR colonoscopy every 10 years • Some countries have lowered the starting age to 45 (e.g., the United States since 2021)

High-risk groups (earlier screening recommended): • Family history of colorectal cancer in a first-degree relative — begin at age 40 or 10 years before the age at which the relative was diagnosed, whichever comes first • Inflammatory bowel disease (Crohn's disease, ulcerative colitis) • Personal history of adenomatous polyps • Hereditary polyposis syndromes (familial adenomatous polyposis, Lynch syndrome)

The home FOB test does not replace colonoscopy — the gold standard for both diagnosis and polyp removal. However, it serves as a convenient, non-invasive, and inexpensive screening tool that can identify individuals who need further investigation, without requiring bowel preparation, sedation, or a clinic visit.

How to perform the FOB test at home?

The iLabU FOB test (model TFO-602H) is an immunochromatographic cassette test that specifically detects human hemoglobin in stool. Unlike older guaiac-based tests, it does not require any special dietary restrictions before testing.

Preparation: • Do not test during menstruation or active hemorrhoid bleeding, as external blood can cause a false positive. • Discontinue aspirin and NSAIDs (ibuprofen, naproxen) 48 hours before testing — these medications can cause microscopic gastrointestinal bleeding. • Collect the stool sample on a clean surface (paper or plastic liner), not directly from toilet water.

Procedure: 1. Unscrew the cap of the buffer tube with the attached applicator. 2. Pierce the stool sample in at least 3 different spots with the applicator tip — do not scoop. 3. Reinsert the applicator into the buffer tube and shake vigorously. 4. Dispense 2 drops of the extracted solution onto the test cassette. 5. Read the result at 5 minutes.

Two lines (C and T) indicate a positive result — hemoglobin has been detected in the stool.

What does a positive FOB result mean?

A positive FOB result means that hemoglobin was detected in your stool, but it does not automatically mean cancer. The causes of occult blood span a wide spectrum:

Benign causes (most common): hemorrhoids, anal fissures, non-neoplastic polyps, inflammatory bowel disease, diverticulosis.

Concerning causes: adenomatous polyps — these are precancerous growths that can be removed during colonoscopy before they become malignant.

Serious causes: colorectal cancer, gastric cancer, angiodysplasia.

Statistically, out of every 100 people with a positive FOB result, 3–5 will be diagnosed with colorectal cancer, 20–30 will have polyps (many removable and precancerous), and the majority will have a benign explanation. However, every positive result requires a medical consultation and, in most cases, a follow-up colonoscopy to identify the source of bleeding.

A negative result does not guarantee the absence of disease — a single FOB test has a sensitivity of approximately 70–80%. This is why regular repeat testing is essential to achieve cumulative detection rates above 90%.

Related product

• Fecal Occult Blood (FOB) Test 15.00 PLN

Frequently asked questions

How often should I take the FOB test?

Guidelines recommend an FOB test every 1–2 years for adults over 50, or from age 40 if there is a family history of colorectal cancer. Regular repetition significantly increases the cumulative sensitivity of screening, catching lesions that a single test may miss.

Can hemorrhoids cause a false positive?

Yes. Hemorrhoids are the most common cause of a positive FOB test. However, a positive result should never be dismissed on the assumption that hemorrhoids are the sole cause — a doctor's consultation is always necessary to rule out more serious pathology, usually via colonoscopy.

Does the FOB test replace colonoscopy?

No. Colonoscopy remains the gold standard for colorectal cancer diagnosis and allows for simultaneous polyp removal. The FOB test is a screening tool designed to identify individuals who would benefit from colonoscopy. It is particularly valuable because of its simplicity, low cost, and non-invasive nature.