Dominos crystals problems.

My domino has been having issues for 3 years. At first it was struvite crystals. This diagnosis was obtained thru a sterile urinalysis. He was put on hills C/D and recently royal canin urinary so.
About 2 monthd ago he blocked, they put in a catheter and flushed his bladder.
A follow up ultra sound a month later revealed stones still present. He underwent a cystotomy 2 weeks ago. The results of the labs in the stones were not common.
The exterior of the stones are phosphate and calcium oxolate and urate. The interior of stones are calcium oxolate and urate.
So tomorrow he goes in for a bile acids test, which is a blood draw after fasting then a meal then another blood draw.
Can anyone give me some insite if you have had experience with this?
Thanks

Sorry to hear of your kitty's troubles. Urate stones are very rare. Coincidentally, there was another poster very recently whose cat had urate stones removed as well. The only thing I really know about urate stones is that they are more likely to occur in cats with liver shunts which is probably what the bile acid test is for and that a low purine diet is recommended to help prevent formation of more of these stones.

Do you have a recent urinalysis? Do you test you cat's urine pH at home? Calcium oxalate stones are more likely to form in more acidic urine which could have been caused by the years on c/d which has added urine acidifier to address the usually too alkaline pH in which struvite crystals form.