Performing a percutaneous kidney biopsy

Table 1 Important considerations for kidney biopsy preparation

Checklist	Explanatory notes
Fasting	Patients should be fasted if procedural sedation is anticipated
	Practices vary and local protocols should be followed
Medical imaging	Urinary tract imaging should be requested to exclude structural kidney disease and confirm suitable anatomy for biopsy
	Reduced cortical thickness and bipolar kidney length have been associated with an increased risk of haemorrhagic complications[5-9] and poorer diagnostic sample adequacy[10,11]
	There is no evidence that a solitary or horseshoe kidney predisposes to a higher rate of post-biopsy haemorrhage[12,13]; however, patients risk the loss of their only kidney in the event of misadventure
	Percutaneous biopsy is traditionally avoided in cystic kidneys. Sufficient renal parenchymal tissue is difficult to obtain and there are theoretic risks of haematoma or infection from cyst trauma
Urine culture	Urine cultures should be requested prior to biopsy to identify bacteriuria, which may increase the risk of UTI
	An audit of 1812 consecutive biopsies identified only 2 cases of post-procedure UTI[14]
	Abscess formation, pyomyositis, and bacteraemia have been reported after biopsies of patients with active pyelonephritis
Blood pressure	Hypertension is a risk factor for major bleeding, particularly when the systolic blood pressure exceeds 160 mmHg[15]
	A systolic blood pressure of 160 mmHg is a commonly accepted upper limit for kidney biopsy
	Hypertension on the day of biopsy often leads to patients having their procedure postponed. The effect of rapidly lowering blood pressure with antihypertensives immediately before biopsy are unknown
Haemoglobin	The approach to pre-biopsy anaemia is contentious and based on anecdotal evidence. Many local protocols recommend a pre-biopsy haemoglobin greater than 100 g/L
	Anaemic patients are more likely to require a blood transfusion after biopsy, especially when the pre-procedure haemoglobin is less than 80 g/L[18,22]
	In observational studies the need for transfusion was independent of clinical bleeding events[21], implying that transfusion rates were mediated by other factors such as comorbidities or protocolised haemoglobin targets
Coagulation studies	Kidney biopsy is classified by the Society of Interventional Radiology as a high-risk procedure for bleeding[16]
	The international normalised ratio must be less than 1.5 and the platelet count greater than 50 ×109/L prior to kidney biopsy[17,18]. Data supporting these recommendations are poor[17,19,20]
	The utility of the APTT is unclear. The Caring for Australians and New Zealanders with Renal Impairment guidelines recommend checking the APTT pre-biopsy but do not comment on its interpretation[18]

APTT: Activated partial thromboplastin time; UTI: Urinary tract infection.