What does the term "occult blood" indicate?

The term "occult blood" refers specifically to blood that is not visible to the naked eye. This blood is typically present in bodily fluids such as stool or urine, but cannot be seen without the aid of laboratory testing. The detection of occult blood is important in clinical settings, as it can indicate various medical conditions, such as gastrointestinal bleeding or other internal bleeding situations.

The other options relate to different contexts of bleeding. Visible bleeding directly refers to blood that can be seen, while blood in urine specifically indicates hematuria, and blood from an external source typically describes wounds or injuries. Understanding that "occult blood" signifies blood that is hidden and requires testing to detect is crucial in the medical field, as it helps guide further diagnostic processes and treatment approaches.