Of 3 tests on different days albumin/creatinine ratio was 37.77, 34.09, & 36.87. i am healthy and exercise often. is this kidney damage?

Maybe: This is just a little bit more albumin in the urine than most other healthy people, most of whom have 30 or less. I wouldn't spend time or energy worrying about it. Often we never find the reason that otherwise-healthy folks have a bit of protein in the urine; I wouldn't be surprised if you had orthostatic proteinuria which easy enough to check for. Best wishes.

Borderline: Ratios are sometimes not the best measure. You may wish to get 24 urine protein level done to establish if you have proteinuria. See this site for more info. http://nkdep.nih.gov/resources/quick-reference-uacr-gfr-508.pdf