Fecal (Stool) Occult Blood (FOBT)

Clinical definition of the Fecal Occult Blood test
Fecal occult blood testing (FOBT) aims to detect subtle blood loss in the gastrointestinal tract, anywhere from the mouth to the colon. It is often used in clinical screening for a particular disease, but it can also be used to look for active occult blood loss in anemia or when there are gastrointestinal symptoms.

Why is the Fecal Occult Blood test done?
To screen for gastrointestinal bleeding which may be an indicator of colon cancer or as a part of a routine examination to screen for colon cancer. A secondary use of FOBT is to look for a cause of anemia, such as blood loss from a bleeding ulcer.

What are the common signs/symptoms when the Fecal Occult Blood test is done?

  • Fatigue
  • Low hemoglobin and hematocrit
  • Unusually dark stools

Who should do the Fecal Occult Blood test (Target population)?
Persons showing the symptoms of a gastrointestinal infection.

What should I do before the Fecal Occult Blood test?

Specimen type

Specimen collection procedure

Preparatory instructions before the test *


Hands must be washed before beginning the procedure.

Pass the stool specimen directly into the clean stool container provided.

DO NOT pass the specimen into the toilet.

DO NOT urinate on the specimen or into the container.
DO NOT allow any water to mix with the specimen.

DO NOT contaminate with toilet tissue.

The specimen must be returned to the lab within 1 hour of collection.

No special preparations required.

*Subjects suffering from any illness or on oral or injectable medications are advised to consult their physician prior to requesting any tests or procedures.

How do I interpret my Fecal Occult Blood test results?

Reference Range*




Inference: The FOBT test is normally negative. A positive test result will tell your doctor that you have abnormal bleeding occurring somewhere in your gastrointestinal tract. This blood loss could be due to ulcers, diverticulosis, bleeding polyps, inflammatory bowel disease, hemorrhoids, from swallowed blood due to bleeding gums or nosebleeds, or it could be due to benign or cancerous tumors.

‘*A Reference range is a set of values which helps the healthcare professional to interpret a medical test. It may vary with age, gender, and other factors. Reference ranges may also vary between labs, in value & units depending on instruments used and method of establishment of reference ranges’

Diseases/conditions related to the Fecal Occult Blood test

  • Upper or lower gastrointestinal bleeding
  • Peptic ulcers 
  • Colorectal cancer 
  • Gastric cancer
  • Colon cancer
  • Hemorrhoids
  • Anal fissures
  • Colon polyps
  • Peptic ulcers
  • Ulcerative colitis
  • Gastroesophageal Reflux Disease (GERD)
  • Crohn's disease
  • Irrational use of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen, and naproxen

Other tests related to the Fecal Occult Blood test

  • Stool Routine Test
  • O&P
  • Clostridium difficile toxin
  • Stool Culture
  • Entamoeba histolytica antigen tests
  • Giardia
  • Cryptosporidium

Synonyms : Hemoccult, Guaiac smear test
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Stool for Occult Blood