Renal biopsy

At a glance

• A biopsy is worth doing when the result would change treatment or prognosis and the kidneys are still salvageable.
• Main indications: adult nephrotic syndrome, nephritic syndrome or RPGN, unexplained AKI that isn't recovering, proteinuria over 0.5 g/day with haematuria, systemic disease with kidney involvement (lupus, vasculitis, myeloma), and transplant dysfunction.
• Serology sometimes replaces it: a positive anti-PLA2R with typical membranous nephropathy, or a confirmed genetic diagnosis of Alport syndrome.