Stool Occult Blood Test
A test that checks a stool sample for hidden (“occult”) blood — blood you cannot see just by looking — which can mean there is bleeding somewhere in the digestive tract.
Stool Occult Blood Test
A test that checks a stool sample for hidden (“occult”) blood — blood you cannot see just by looking — which can mean there is bleeding somewhere in the digestive tract.
Also known as
- Fecal occult blood test
- FOBT
What it measures
- Whether blood is present in a stool sample
Why a doctor may order it
It is commonly used to screen for colorectal cancer before symptoms start, and it may be used to look for other causes of bleeding in the digestive tract or to help find the cause of anaemia. A doctor may also ask for it if you have symptoms that could involve digestive-tract bleeding.
What it helps evaluate
It can show that blood is present in the stool, but cannot diagnose any condition. If blood is found, other tests — most often a colonoscopy — are used to find the cause.
Preparation
Many versions need no special preparation, but for some kinds, certain foods, supplements and medicines (such as aspirin and other NSAIDs) can affect the result. Follow the instructions you are given.
Fasting
No fasting is needed. Some tests ask you to avoid particular foods or medicines — follow the instructions.
Important considerations
- You usually collect the stool sample yourself with a kit that includes instructions.
- Blood in the stool has many possible causes, including haemorrhoids, ulcers and polyps.
Discuss results with your doctor
Blood in your stool, black stools or unexplained weight loss should be discussed with a doctor promptly.