70 years old and a high amount of red blood cells, kidney appeared to be 3% bigger than before. with hepatitis since a while ago as well. dangerous?

Red blood cells: It's hard to give detailed response b/c it's unclear if you're concerned about the red blood cells, kidneys, or hepatitis (or all 3!) however, there is a disorder when someone produces too many red blood cells called polycythemia vera. People tend not to have symptoms with mild disease, but at higher levels they are at risk for blood clots. Hope this is somewhat useful.