Outpatient Kidney Biopsy: A Single Center Experience and Review of Literature.

Background: A kidney biopsy is an important tool in managing kidney diseases. Bleeding is the most significant complication. The biopsy can be performed as an inpatient or an outpatient procedure with a shorter post-biopsy bed rest and monitoring period. It is cost-effective, but raises some questions about patient safety. At Helsinki University Hospital, the majority of elective kidney biopsies have been performed as outpatient procedures since 2010. The aim of this study was to retrospectively evaluate the safety and risk factors of this protocol.

Methods: We collected data from all patients undergoing an elective outpatient biopsy of a native or transplanted kidney following the outpatient protocol between January 2011 and February 2016. We recorded the data on the biopsy procedure and complications: bleeding (hematoma or macrohematuria), severe pain, death, or "other" (infection, accidental puncture of another organ). A complication was classified as major, if it required interventions such as transfusion or radiological or surgical intervention.

Results: Over a 5-year period, 824 (448 native and 326 transplant kidney) patients were biopsied. In total, 94 (11.4%) had a complication, but only 4 patients (0.5%) had a major complication; no deaths were recorded. All major and 70 minor complications emerged during post-biopsy monitoring (4-6 h). Patients with complications were younger (p = 0.001), female (p < 0.001), and had lower hemoglobin (p = 0.001) than those without. Transplant biopsies were associated with fewer complications than native kidney biopsies (p= 0.002).

Conclusions: In selected patients, an outpatient kidney biopsy is a relatively safe procedure.