Medical Q&As

Occult blood - colonoscopy?

My partner has recently undergone a complete medical. Four out of twelve stool samples tested positive for occult blood. He is being sent for a colonoscopy. He is 41 years old. His father died age 55 of colon cancer. What will the colonoscopy examination be targeting?

A positive occult blood test means that the stool sample tests positive for blood even though blood is not visible in the stools. Colonoscopy involves the insertion of a flexible scope into the colon through the anus thereby facilitating a visual inspection on the interior of the colon. Techniques for visualising the interior of the colon are an enormous step forward from the previous indirect radiographic techniques that involved dye insertion. If a lesion is present in the colon it is usually possible to see it through the scope and make a visual diagnosis. It is also possible to take a sample of tissue through the scope and send it to the laboratory for microscopic examination. Some families have a history of carcinoma of the colon but the malignant change is sometimes preceded by the presence of polyps in the colon. If your partner has polyps then the procedure of colonoscopy would permit the removal of such polyps, which would be a curative procedure in itself. In that event follow-up colonoscopy would be recommended at appropriate intervals in order to establish that the polyps had not re-grown. There are several other causes for occult blood and the diagnosis should not be regarded as being synonymous with a diagnosis of cancer.