Elevated Creatinine & Normal BUN Levels

i saw my doctor today, and he was puzzled about why i had a relatively high creatinine count (1.48) and a totally normal BUN level.   what types of circumstances or factors can generally be conducive to such conditions.  my doctor has not decided for certain yet (he wants to wait a couple of months and duplicate the testing), but he's considering sending me to see a nephrologist.  meanwhile, i'm wondering if it could be related to something i may be eating or drinking (or not eating or drinking), some medications or supplements.

i have been vegan for nearly a year and drink a substantial amount of white tea (as well as other, non-cafine teas) each day and some plain filtered water as well.  would appreciate any ideas on what could be going on.  also,  in recent months, i was also having elevated liver function reading in my blood work, and it appeared to be (at least) partially due to some meds i've been on.  the liver functions have just about come down to normal ranges, but now for some (possibly or not, related) reasons, my kidneys seem to be acting up.  thanks for any info on this.

all other blood chemistry and hematology results were within normal ranges.