How long would you wait before repeating a kidney biopsy procedure in a patient with inadequate tissue obtained on a prior attempt which was also complicated by a small perinephric hematoma?

I don't think we have any evidence to guide this decision. Somewhat depends on the urgency of the need to get tissue and how easy the first biopsy attempt was. If it is thought that the path to the next biopsy would need to go through the hematoma and no urgency could wait until resolved but usually...

It all depends on the reason for kidney biopsy. I have done another biopsy as early as 2 weeks later or sometimes I have decided to forego the biopsy all together. The second time around especially if there is a hematoma, I probably decide to have interventional radiology do the biopsy.