kidneys and bloodwork readings?

I have a cat that's been on chemo and her kidney levels had been fine until
very recently.

They found an infection and suspect it's the culprit, but it has raised her
BUN level to 38 (normal range 14-36) and her Creatinine level to 3.3 (normal
range 0.6-2.4).

I was hoping someone out there with direct experience with these blood
readings could tell me how bad off her kidneys are from the above numbers?
Obviously they're not normal, but I was hoping someone with a common frame
of reference could tell me how this compares to true CRF cats.

She's on antibiotics now and seems to be responding, still has an appetite,
etc. but I'm wondering if these numbers will continue to be high or if
they'll resolve when it's caused by an infectoin.

Thanks.