My husband's doctor said that once kidney function drops below 15% that you need dialysis.My husband was at 2% when we discovered that his kidneys had failed.He went to the doctor because his blood pressure was high.His doctor put him into the hospital to get his pressure down.That is when they discovered the kidney failure.Some of the other signs that we didn't know about at the time were:A puffiness in his face and foot(he only had one leg),trouble urinating(it would start then stop),pain is his lower back,very itchy,and just a general feeling of being unwell.If you think something is wrong go to a doctor.We almost waited too long.