The venous blood gases - they take blood from the dog and use a special analysis machine to determine the pH, the 'base excess', and several other blood chemistries. I don't pretend to know what they all mean, but I know what the important values are from experience and from reading the protocol. (Linda, maybe you can enlighten us more?) It takes a special machine to read this and not all vets have them. Many vet specialty groups do and so do some vet emergency clinics - in some areas, it has to be done at a people hospital. The machine is called an I-STAT. The blood gases are done after a diagnosis of Fanconi, which is made by finding sugar in the urine and normal or even low blood glucose in a regular blood panel.
The sugary urine is usually the first symptom - even a trace amount of sugar in the urine is NEVER a good thing. That's why we strip test monthly, to see if the dog is spilling sugar.
The UTIs have to be watched for in a dog with Fanconi. As I said, they frequently don't show up on urinanalysis; most of us with Fanconi dogs go by symptoms - depressed appetite, "accidents" or night leakage, general lethargy, and sometimes pain in the back or back legs. When we see these symptoms, we have the vet give us a 2 -3 week course of antibiotics (usually Clavamox or Baytril) even if the urinanalysis doesn't show an infection. There are some Fanconi dogs that are so prone to these hidden UTIs that they have been placed on 'pulse therapy' with a couple of weeks on antibiotics on a regular basis.
Hope this explains things better…there is a group for owners of Fanconi dogs, and there are people on there with much more knowledge than I have. Should any of you ever have to deal with this, it's a fabulous resource and a terrific support system.
I know this was long, sorry!