Investigations

• clinical signs suggestive of primary renal disease, vascular lesions or systemic disease 
• no obvious cause for acute renal failure 
• suspected acute interstitial nephritis or drug-induced vasculitis 
• oligo-anuria thought due to ATN persists beyond 3 weeks without perpetuating factors 

Why?

• In selected patients, biopsy findings alter management in 70% of cases (95% CI: 55% to 87%) ^c
• Complications are uncommon, but may be severe ^c

Bleeding and unsuitable samples are the commonest complications

Complications	% (95% CI)
clinically important bleeding c	4.1% (0.9% to 7.4%)
unsuitable sample	1.4% (0.0% to 3.3%)
nephrectomy for prolonged bleeding (> 30 days)	0.7% (0.0% to 2.0%)




 

	Italian Registry b	French tertiary centre b	English tertiary centre b	Spanish tertiary centres c
% patients with acute renal failure biopsied	-	12%	13%	6%
glomerulonephritis	19%	29%	25%	39%
vasculitis	20%	32%	-	22%
acute tubular necrosis (ATN)	8%	24%	17%	10%
acute interstitial nephritis	11%	13%	11%	10%
HUS/TTP	3%	-	12%	-
myeloma	5.1%	-	2.4%	-