Background Kidney biopsies are essential for optimal diagnosis and treatment. Purpose To examine if quality and safety aspects differ between types and sizes of biopsy needles in native and transplant kidneys. Material and Methods A total of 1299 consecutive biopsies (1039 native and 260 transplant kidneys) were included. Diagnostic quality, needle size and type, clinical data and complications were registered. Eight-three percent of the data were prospective. Results In native kidney biopsies, 16 Gauge (G) needles compared to 18 G showed more glomeruli per pass (11 vs. 8, P < 0.001) with less complications. Sub-analysis in native kidney biopsies revealed that 18 G 19-mm side-notch needles resulted in more major (11.3% vs. 3%; odds ratio [OR], 4.1; 95% confidence interval [CI], 1.4-12.3) and overall complications (12.4% vs. 4.8%; OR, 2.8; 95% CI, 1.1-7.1) in women than in men. If the physician had performed less compared to more than four native kidney biopsies per year, minor (3.5% vs. 1.4%; OR, 2.6; 95% CI, 1.1-6.2) and overall complications (11.5% vs. 7.4%; OR, 1.6; 95% CI, 1.1-2.5) were more common. In transplant kidney biopsies, 16 G needles compared to 18 G resulted in more glomeruli per pass (12 vs. 8, P < 0.001). No differences existed in frequency of biopsy complications. The localization of performing biopsies was not a risk factor to develop complications. Conclusion Kidney biopsies taken by 16 G needles result in better histological quality and lower frequency of complications compared to 18 G. For native kidney biopsies the performer of the biopsy should do at least four biopsies per year.
Keywords: Urinary; biopsy; complications; interventional; kidney; percutaneous.