So monday EGFR was 22 wednesday 29- I go back tomorrow- How does this happen- I was fine last Aug -- Dr took blood work and never never mentioned anything? So what does this mean? I am 38 BP is good I am not Diabetic, a little over weight. Does anyone know Can EGFR be effected by something I ate of drink before the test or can it be effected by something I ate? Can it go back to a normal reading or is this permanant?