Test Detail
Interpreting Results

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Dr. Shreya Gupta
BDS, MDS - Oral and Maxillofacial Pathology
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MBBS, MD (Pharmacology)
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Stool For Occult Blood

Stool For Occult Blood
You need to provide
This test is for
Male, Female
Test Preparation
  1. Inform your doctor if you are on any medication.


What is Stool For Occult Blood?

The stool test for occult blood checks the presence of blood which is not visible to the naked eye. Occult blood means the hidden blood which you can't see. Occult blood in the stool can indicate bleeding in the gastrointestinal tract which can be due to asymptomatic ulcerated lesions of the GI tract, polyps, hemorrhoids, diverticulosis, Ulcers, and Colitis (a type of inflammatory bowel disease). The presence of blood in the sample may also be a sign of colorectal cancer. A stool for occult blood test can be used as a screening test for early diagnosis of colorectal cancer. It can also help in analyzing the most effective treatment which could be used.

Why is Stool For Occult Blood done?

  • To screen for digestive tract bleeding, which may be an indicator of colon cancer, asymptomatic ulcerated lesions of the GI tract, polyps, hemorrhoids, diverticulosis, and Colitis (a type of inflammatory bowel disease).
  • To evaluate unexpected anemia

What does Stool For Occult Blood Measure?

Invisible blood (occult blood in stool) can be a screening test of carcinoma colon (a type of cancer) and can help in early diagnosis and management. Most cases of colon cancer begin with benign intestinal polyps which are relatively common in people over the age of 50. Mostly, these polyps may not cause any health problems, but some can become cancerous. These finger-like growths which extend into the intestinal cavity (lumen) or the rectum. They can be fragile and may bleed occasionally when fecal mass brushes against them. This can be detected by a fecal or stool occult blood test. This small amount of blood may be the first and sometimes the only sign of early colon cancer thereby making a stool for occult blood a valuable screening tool for colorectal (colon and rectal) cancer.

It is recommended that at least three stool samples should be collected on different days. The American Cancer Society has stated that a single test performed at the time of a digital rectal exam in a health practitioner's office is not recommended because the sample may not be sensitive enough to screen for cancer. The home FOBT or FIT is recommended because the collection of stools on three different days increases the chance of detecting cancer. Furthermore, it is recommended that those who choose this method of colon cancer screening should get screened every year.

Interpreting Stool For Occult Blood results


Normal result: negative means occult blood is not present in the stool.

Positive stool occult blood test means that there is bleeding somewhere in your digestive tract asymptomatic ulcerated lesions of the GI tract, polyps, hemorrhoids, diverticulosis, Colitis, and colorectal cancer. If stool for occult blood is positive, then additional tests may be required such as colonoscopy in order to detect the exact location and cause of your bleeding.

Answers to Patient Concerns & Frequently Asked Questions (FAQs) about Stool For Occult Blood

Frequently Asked Questions about Stool For Occult Blood

Q. Is there any preparation required before the test?
Inform the doctor about the medications you may be taking. No other specific preparations are usually required before this test.
Q. How is stool test for occult blood done?
The method of collection and testing depends on the test procedure used and can vary from laboratory to laboratory. For the guaiac-based test, the laboratory will provide three test cards. Separate stool samples are collected on three consecutive days and for each test, a stool sample should be collected into a clean container and should not be contaminated with urine or water. A test card is labeled with the person's name and the date. A thin smear of stool is put onto a designated area on the card and allowed to dry. Once it is dry, it is stable for several weeks at room temperature. When all the consecutive samples have been collected and dried, the test cards are returned to the health practitioner or laboratory, usually by mailing them. With the OTC flushable reagent pad/tissue method, a test pad/tissue is placed in the toilet after a bowel movement. The pad contains a chemical that produces a color change when blood is present. The person doing the test watches for the characteristic color change and records the findings on a report form. Like the gFOBT, this test is usually done on three consecutive days and then the completed form is returned to the health practitioner. The use of toilet bowl cleansers or the presence of blood-derived from urine or a woman's menstrual period may alter results. With the fecal immunochemical tests (FIT), a common approach is to use a special long-handled brush or any other device in order to collect a sample from the surface of a stool sample. The brush or device is then used to transfer the sample to a special collection card. After the card is allowed to dry, it is returned to the laboratory for further analyses.
Q. Why more than one stool sample is required?
Bleeding, especially from polyps and tumors, is periodical. Therefore, blood is not uniformly distributed in all stool samples. This means an exact interpretation of results from a single test cannot be made. Hence, taking three different samples on three different days can increase the chances of detecting occult bleeding.
Q. What other tests are available to screen carcinoma colon?
Other available tests to screen carcinoma colon include Sigmoidoscopy which is an endoscopic examination of the rectum and lower colon. If polyps are found, they may be removed during the procedure and examined by a pathologist to see if cancer is present. Screening with sigmoidoscopy should be done once every 5 years; Colonoscopy which is a more thorough examination of the rectum and entire colon using a flexible endoscope. If polyps are found, they may be removed during the procedure and examined by a pathologist to see if cancer is present. This procedure is recommended for screening every 10 years; CT colonoscopy (virtual colonoscopy) which uses computed tomography to visualise the entire colon. The recommended screening interval is 5 years and Double-contrast barium enema which is a series of X-rays of the colon and rectum is taken. It is recommended every 5 years.
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Gen-X Diagnostics is a unit of ARA Healthcare Pvt. Ltd. founded by leading applied research scientist Dr. Rama Mukherjee. Gen-X specializes in the field of molecular diagnostics, focusing on the development of genetic, biological and molecular diagnostic services. It is one of the first of its kind R&D Company focusing on development of genetic, biological and molecular diagnostic services with an intention to assisting its global partners in shortening the cycle and lowering the cost of drug...
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