During a physical exam, a retired bus driver has a positive occult blood test. What could this indicate?

A positive occult blood test in a retired bus driver can signify the presence of blood in the gastrointestinal tract, which is often associated with conditions affecting the lower gastrointestinal system. Among the options presented, colorectal cancer is a common and significant condition that can lead to gastrointestinal bleeding, resulting in a positive occult blood test.

Colorectal cancer often progresses silently in its early stages and may not present with obvious symptoms until it has advanced. Testing for occult blood is a routine part of screening for colorectal cancer, especially in patients over the age of 50 or those with risk factors like age, family history, or lifestyle factors.

While gastric cancer can also lead to occult blood in stool, it is less common than colorectal cancer, especially in the absence of gastrointestinal symptoms specific to the upper GI tract. Diverticulitis may cause bleeding, but it is typically considered more acute and related to diverticular disease rather than a general screening concern. Hepatic failure may produce gastrointestinal bleeding as well, but it does not typically cause a positive occult blood test directly related to lower GI bleeding.

Given these considerations, the indication of a positive occult blood test aligns most closely with a suspicion of colorectal cancer, making it the most plausible interpretation of the test result.