[horsenut_8700]

Apparently I did miss that. I apologize. Treating cats with urinary issues can be frustrating and a lot of trial and error.

[Marshfield]

It's not impossible to confirm a bladder infection without culture. If there's a lot of white blood cells in the urine that's a very good indicator of a bladder infection.
She is not diabetic and the urine was concentrated. Her blood work was all within normal parameters.

The fact that her urine was well concentrated makes a UTI very, very unlikely. The WBC's could all be inflammation and don't necessarily signify infection. Lots of cats with sterile cystitis have high WBC in the urine but no bacteria. There is no benefit to treating sterile cystitis with antibiotics. I wouldn't trust an in house UA to make the call on the presence of bacteria. We compared in house to send out lab and found insane amounts of false positives in house due to how quickly the in house stain becomes contaminated.

[grayarabpony]

The vet's office sent both the blood and the urine out for analysis. That was my understanding. The lab offers a free U/A with the blood work.

Since there's no treatment for sterile cystitis anyway and at this time she's not exhibiting glaring symptoms, what difference does it make?

My main concern with her was hyperthyroidism anyway.

[SquishTheBunny]

My cat has had a few bouts of sterile cystitis. Cultures showed no infection.

What worked was an anti-inflammatory (metacam) in conjunction with cosequin for cats.

He was already on a tin food. During one bad flareup, he also received buprenorphine.

Since he has been on the cosequin, there have been no further issues.

[nuevaburro]

We compared in house to send out lab and found insane amounts of false positives in house due to how quickly the in house stain becomes contaminated.

Stop using stained to look for bacteria. We only diagnose presence of bacteria if we see them in unstained sediment. If you see WBC and bacteria, occam's razor says infection.

[grayarabpony]

Well for the doubters out there, my cat really did/ does have a UTI. A week ago she was actually symptomatic for the first time (looked uncomfortable, and then I found she was leaking blood), so I took her to the after hours vet. Blood work, U/A, culture, xray, abdominal ultrasound, the whole nine yards. She is very close to being hyperthryroid, and the vet told me that cats with thyroid problems can have problems with UTIs. Her blood kidney values are good (although I realize that high thyroid can skew those values to normal); the fact that she is concentrating her urine well makes kidney failure very unlikely at this time per the vet. The culture showed bacterial growth (E. coli) sensitive to Clavamox.

Apparently the 2 weeks of Clavamox in January wasn't enough.

She is to finish off her course of antibiotics, get another culture a week after that, and another T4 test in 2 months.