Update: crystal urate

I took one of my female to the vet yesterday, she had 2 lots of urate that consisted completely of yellow crystal; the vet said he'd never seen anything like this before. I suggested it might be gout or excessive calcium intake. He checked her physically and can't find anything abnormal, and the gecko is moving around just fine. I also asked about kidney problems, he said at the age of 1.5yrs, there is still a possibility for kidney disease; but he'll need to do a blood test which he hadn't done to a gecko before. He'll be away for 10 days starting next week, in the meantime, he wants me to give this girl a half hour warm bath every night, decrease supplements, and if the problem persists, he'll do the blood test. But he'll need to do some research first...(that's why I'm worried).

My question: he commented yesterday that he'll get the blood from her belly, from the "inverse-Y "; is this really the place to draw blood??