With renal failure you want to use a low phosphorus diet as it appears to be the phosphorus that is an issue.
When the kidneys are not functioning right toxins can build up making the dog feel pretty miserable and unwilling to eat.
Drinking is better than not drinking in this situation and you might need to get the electrolytes in her through subcutaneous fluids. Some vets will teach clients how to do that at home and others may offer reduced rates for regular fluid 'fill ups' at their clinic.
You might call and ask your vet about that to see if it helps her be interested in eating.
Do check in with them today to tell them she is not eating for you. They may want her in before the weekend.
This site has some recipes for dogs with kidney issues
http://www.b-naturals.com/newsletter/kidney-diet/
You might try giving her some NutriCal a sticky supplement available at many pet supply stores to see if that jump starts her appetite. You give it right in the mouth like medicine.
Hope this helps you!
Dog Expert:Rescue, Train,Breed,Care
30+ yrs dog home vet care & nursing, rescue, behavior&training, responsible show breeding, genetics
My deepest sympathies on your loss. There is never a good time to lose a good dog.
If you have not seen www.petloss.com and the rainbow bridge story it may bring you some comfort. Tessa was lucky to have such devoted owners.
Thank you for the above accept.