04/10/2026
Recognizing the sight of blood in urine, the most common first sign of bladder cancer, is often the impetus that leads people to a diagnosis. But for those with colorblindness, who usually have difficulty seeing red, that warning sign is more likely to go down the toilet unnoticed.
Now a study by Stanford Medicine researchers and collaborators has found that missing this early sign can have serious health consequences.
A study led by Stanford Medicine found that the earliest sign of bladder cancer — blood in the urine — may be invisible to people who are colorblind, increasing their risk of dying from the disease.