Adequacy and safety of pediatric native kidney biopsy using 16- and 18-gauge needles.

Background: The native kidney biopsy is an important diagnostic procedure in pediatric nephrology. Recent meta-analyses did not find the size of the needle as a risk factor for bleeding complications, but they were predominantly based on adult studies. There are few papers comparing the safety and core adequacy in pediatric native kidney biopsy.

Methods: We present a large single-center retrospective study performed in a tertiary pediatric nephrology center. Data of children who received a real-time ultrasound-guided native kidney biopsy with a 16- or an 18-gauge needle from 2018 to 2024 were analyzed.

Results: Overall, 1040 children (644 boys) were included, with a median age of 10.25 (6.6; 14.23) years. One hundred three (9.9%) patients experienced bleeding complications. Perinephric hematoma was reported in 86 (8.3%) cases, gross hematuria in 18 (1.7%), and 3 (0.3%) children required transfusion. Multivariate regression analysis revealed the needle size (OR for 16-gauge 2.06, 95% CI 1.22-3.47, p = 0.007) as a risk factor for complications in the overall cohort and in children under 12 years old. The needle size did not affect complication rates in children aged 12-18 years. Inadequate kidney cores were reported in 37 (4.5%) cases; OR for 18-gauge needles (OR 5.08, 95% CI 1.07-24.21, p = 0.041) was found.

Conclusions: Use of a 16-gauge needle reduces the risk of obtaining an inadequate core in comparison with an 18-gauge. An 18G needle has a safety advantage over a 16G needle in children younger than 12 years. A 16G needle is as safe as an 18G needle and should be used for native kidney biopsy in children older than 12 years.