What should I do if there is occult blood in the physical examination?

The so-called occult blood is "potential bleeding", that is, red blood cells can't be observed with the naked eye or under the microscope, but if there is a reaction when tested with test paper, why? Because the hemoglobin contained in the red blood cells will be released when they are destroyed, the urine test stick can detect the hemoglobin reaction.

It may be that the red blood cells themselves dissolve like foam at the end of their life, or that drinking a lot of water weakens the urine and reduces the tension, so the red blood cells burst.