My bun was 20 today. can dehydration cause it to be higher? mine has always been on low end. creatinine is normal, no other symptoms or abnormal tests. i have barely been drinking a bottle of water per day for quite a while?

Yes, there are several things which cause high BUN without affecting much serum creatinine: mild dehydration, eating high protein and taking steroids. Moderate to severe dehydration can increase serum creatinine too along with a much higher BUN, usually the ratio BUN/creat will be above 20 with dehydration. Yes, your intake of only one bottle of water (500 cc) a day is low.

Dehydration is the leading cause of elevated BUN with normal creatinine. Drink enough water daily so that your urine is mostly colorless and may repeat the test in 3-6 months. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, have safe sex, no tobacco alcohol weed or street drugs.