The answer will depend upon the actual test and the value.
There are different blood tests and different considerations for the various blood tests. If the BUN if affected vs. the creatinine, or both, the interpretation would be different. There also is frequently an estimation of kidney function, called eGFR. In the first labs, a lower number possibly indicates better kidney function, while with the eGFR. a lower number possibly indicates decreasing kidney function.
However, for many minor changes in kidney blood tests, particularly of short duration, it is usually a reflection of hydration status. If someone has a lower hydration status, even if not clinically dehydrated, the BUN and creatinine can increase and the eGFR will decrease. Similarly, an increase in hydration status will lower the BUN and creatinine and increase the eGFR.
If the BUN and creatinine are more significantly elevated or the eGFR is more significantly lower, there would be more of a concern that there is kidney dysfunction, but there would need to be further evaluation to confirm whether there truly is kidney dysfunction and the cause of the kidney dysfunction.
If you can get the actual tests and results, then I can make further comment.