yes, please please please get the blood gasses done. Is your vet familiar with the Fanconi Protocol? Don't know how much it is there but it is around $150 for both the blood gasses and blood chemistry here in CT.
My basenji Tayda has Fanconi and Terry is right - the supplements are not a lot of money. The bicarbs, for example, which are the most critical part of the protocol are about $20 for a 1000 count bottle!
please please please find a way to do it! Stormy will be so grateful and will be with you for a lot longer! Fanconi is definitely fatal if not treated but if treated Stormy could be with you for a long long time!