You said

"Obtain a urine sample to evaluate for crystals and bacteria."

Nope.  Not yet because  while the kitty is on the x-ray table you need to do one more thing first.  Being just a little more thorough would have shown you the correct diagnosis.  Good idea to do a urine analysis but that is not the VERY NEXT thing you should do.

View the diagnosis here or close this window and go back and try your very next move.