I know what you mean about it sounding so painful. I can't watch when they do it--the dog picks up on my facial expression and tenseness and then they tense up.
If the tech takes them in another room and someone loves them up while it's being done, they don't even seem to realize it's being done.
(In this case, Mom is a bad influence! I just hate needles so much I can't help but react!
)
Macie is having similar problems but with white blood cells. Clavamox seemed to clear it up, but there were still 3-5 WBC per microscopic field, so we extended the antibiotic for another week. Testing at the end of that week showed even
more WBCs. So we had an ultrasound done--it showed inflammation (cystitis) in the front of the bladder, which is likely due to the infection. They did the cystocentesis to get a sample for a culture and sensitivity and we'll go from there... She needs another ultrasound six weeks after the microscopic tests are clean to make sure the cystitis is clearing up once the infection is gone.
But if your vet is to rule out an infection as the cause and/or find an effective treatment, he's going to need a sterile sample and that's the best way to get it.
I think it's a pretty straight shot to the bladder with little structure in the way, so it's not that tricky a procedure. And it goes really quick!