Yield and complications of kidney biopsy over two decades in a tertiary pediatric center.

Background: Kidney biopsy serves as an adjunct for the diagnosis of renal disease, but it is not always productive. This study evaluated the yield and risks of kidney biopsies performed in 1995-2014 at a tertiary pediatric medical center.

Methods: The medical files of all patients who underwent closed percutaneous biopsy for various indications in native or transplanted kidneys were retrospectively reviewed for patient characteristics, technical and histopathologic findings, biopsy yield, and biopsy complications. Biopsy yield was considered positive if findings confirmed a probable diagnosis or led to a change in clinical diagnosis, disease severity/activity grade, treatment strategy, or prognosis; and negative, if findings were non-informative and in cases of technical failure.

Results: During the study period, 216 biopsies were performed on native kidneys and 84 on transplanted kidneys. In the transplanted kidney group, the most common indications for biopsy were decreased glomerular filtration rate and suspected rejection. Rates of positive biopsy yield were 86.6% in the native kidney group and 82.1% in the transplanted kidney group; the difference was not statistically significant. Significant between-group differences were found in various technical and histopathological parameters, patient age at biopsy, and sex distribution. In the native kidney group, positive biopsy yield was associated with the presence of nephrotic-range proteinuria. Post-procedural complications occurred in three patients (1.3%) with native kidneys, and in one patient (1.1%) with a transplanted kidney.

Conclusions: Kidney biopsy is an efficient and safe procedure in both native and transplanted kidneys and provides helpful diagnostic information in most cases in which it is deemed necessary.