Invisible, or occult, blood in the stool is associated with an increased risk of death from a number of causes, according to a study published in BMJ Gut. These risks include disorders of the circulatory, respiratory, and digestive systems; diseases that affect blood or hormones; neuropsychological conditions; and several types of cancer, including colorectal cancer.
Invisible blood in the stool is detected using a test called the fecal occult blood test (FOBT). The observational study involved 134,000 people in Tayside, Scotland, from March 2000 to March 2016, of whom 131,207 tested negative for occult blood in the stool and 2,714 tested positive.
The researchers found that study participants with positive fecal occult blood test results were nearly eight times more likely to die from colorectal cancer than those who tested negative, after accounting for other factors such as age and gender. Surprisingly, they also found that a positive FOBT result was associated with a 58 percent higher risk of death from all causes. Invisible blood in the stool is believed to be a marker for inflammation in the body, which can indicate a serious medical problem.
Sourced from: Gut