Renal biopsy in nephrotic syndrome

Is renal biopsy necessary in all patients with nephrotic syndrome? Can we perform serological or immunological studies instead?

Jürgen Floege: The pediatricians usually have the approach that they give corticosteroids and if it goes away, it is minimal change [disease]; [they do it] without a biopsy, because it is so difficult in small children to do a biopsy.

In all others I would love to do a biopsy first to get the diagnosis, and not only the diagnosis but also to see how much damage I have in the kidney, which serology will never tell you. Serology can be very helpful, if, for example, you have phospholipase A₂ receptor antibodies in a patient who is massively obese and you cannot do a biopsy. Then the positive serology will tell me this patient has membranous [nephropathy] and I will treat it. That is exceptional. Normally I want to see a biopsy.