What is the faecal occult blood test?
The faecal occult blood test (FOBT) is a test that can detect tiny traces of blood in the stool — such small traces that they can’t be seen with the naked eye. Occult literally means hidden or unknown. The test can indicate the presence of disease at a relatively early stage when stools may appear normal. Two types of faecal occult blood test are commonly used — a chemical test (based on a chemical reaction to haem — part of haemoglobin, the oxygen-carrying molecule found in red blood cells) and an immunological test (using antibodies that recognise haemoglobin).
