Kami just got a gold star from the vet.  She said that hre bladder felt
normal (but they couldn't test urine because she expeled on me when I
tried to get her out of the carrier).  She said that the blood levels
were so good when she was tested two weeks ago, she didn't think it was
worth upsetting her to test again.  Her heart murmur is down to a 1,
she didn't lose any weight as I thought, and she seemed well hydrated.

She said she had seen a number of cats with the same symptoms and could  
not culture anything from urine even if it was bloody and the cats were
in pain.  As such, she gave me cystine for whenever this happens again.  
Then I might be able to put off the ER and take her to the vet during
office hours.  

She's cleared for a few more days of anything she wants to eat, but
then back to her diet.