what is a kidney leak?

Hi, My uro told me it is when your kidney doesn't filter the calcuim back in the blood stream if I am right on this and then it sits in the kidney and forms stones.
I think this is right if I remember correctly. It is passed down from family memembers.
Hope this helps.
sno

I thought it was when the kidney leak protein and proteuria results.

Perhaps there are different kinds of kidney leaks. I've only heard of the one I have had (same as described by 2plus). Have not really explored it further. If the calcium is not filtered by the kidneys at all, how can it be perceived as a leak?