Interesting comments Patp.
The vet seems pretty obsessive compared to my GPs. I had to demand the wee sample bottle from the receptionist before my appointment because I knew the GP would waste time organising things after the appointment. So a couple of minutes with the doc each time and different antibiotics. Only my persistence resulted in the scan,which was fine. So I too question the idea that catching a bitches urine in a sterilised Tupperware box is worse than a GA and possible internal damage and infection!
Are they trying to milk the insurance company, or your wallet.
Obviously the health of your pooch is paramount. But I wouldn't want anaesthetics on a 12 yr old, even if otherwise healthy . Another thought is that with an anaesthetic, couldn't they just draw some wee out with a catheter?
You can probably read on the methodology/protocol by googling the Merck veterinary manual, or one by the Edinburgh Vet School. I'm not medically qualified in any way, so I am just making the same layman's observations as you, all of us being experienced dog owners!
I hope the conditions clear up. I know it can cause feverish conditions. My ancient fatherIn law gets it all the time, and gets very poorly, picks up again, over and over. It's got to be properly cleared up.