Why do gfr levels fluctuate so much? is that normal? i had my gfr checked and it was 110 then the next day went to er for hyponetremia it was 122. (?)

Hydration: The variation you mentioned could be explained by hydration only. However, there are other variables, such as the random variation on creatinine test equipment. Your eGFR is normal. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex.