What are the current clinical indications for renal biopsy?
Jürgen Floege: That is a very difficult question. First of all, you should always consult your nephrologist, because it is a question for which there is no clear answer. You always have to ask yourself, “Is my patient in danger?” and “What do I want to know from the kidney biopsy? Do I simply want to make a diagnosis?” But then you have to ask yourself, “What is the consequence?”
I think most of us would agree that if you have nephrotic syndrome, that is a case for kidney biopsy. If you have acute kidney failure of unknown origin and it does not recover quickly, that is a situation for kidney biopsy. If you have a very rapid loss of kidney function and, let’s say, an active urinary sediment, that is an indication. But also it is the patient with some degree of renal impairment, some degree of proteinuria, where he or she may want to know, “What do I have?” and “Do I have a risk of going to a kidney replacement therapy?”; that is an indication.
There is a relative consensus not to do a kidney biopsy if your kidney function is below 30% and you have small kidneys on renal ultrasound, where you will simply find scars and often you will not be able to say what this patient had.