Blood still in urine

Well so far cassie has had blood work, xrays she has been catheterised and urine sent for microbiology been on antibiotics and she still has +++ blood on her urine dip test and all results have been normal or within the required range. Today she is in for a ultrasound and im really hoping they find the problem so we can fix her. Has any one else had this with there dog who could offer advice as myself and the vet are at a loss as is my pocket lol. also any healing vibes for her would be much appreciated as im very worried about her it must be time for her to have some luck

Yes we had this with one of ours

I presume the Vet has tried a different longer course (up to six weeks) of antibiotics?

No not had 6weeks worth about a months but her probs got worse yesterday as when they shaved her to do her ultrasound they discovered a lump so they biopsied it and it was a mast cell tumour so shes off to have that removed fri and c if theres a link