My husband returned to GP yesterday with results of abdomen/kidney ultrasound which showed kidneys slightly shrunk 8cms, cortical thickness 9mm right 11mm left. I asked if he should see a nephrologist and she said no, only if eGFR goes down to 30. She hasn't tested for potassium or protein. She didn't mention diet until I asked and then gave us an information sheet about low salt diet. My husband is 82 and I know eGFR does decrease with age but not to this extent. The GP hasn't searched for a cause either. I would appreciate your views.