Doctors like nice concrete numbers, but 15% is just a guideline for when they want you to start. Some people feel horrible at 20% and want to start then, some do fine at 10% without dialysis. It's best to decide based on how the patient is feeling. Common symptoms - swelling and fluid retention, a reduction in urine output, constant nausea, a metallic taste in the mouth that affects the appetite, an ammonia smell in sweat, headaches, fatigue. I don't know about a lapse in judgment - but I'm sure I was a lot crabbier than normal - I felt horrible!