Balancing Glomerular Adequacy and Bleeding Risk in Native Kidney Biopsy: A Multicenter Cohort Study of Multiple Needle Passes

Abstract Rationale & Objective Whether performing multiple needle passes during adult native kidney biopsy increases clinically significant bleeding is unclear. We evaluated the association between needle pass number and major bleeding complications and hemoglobin decline. Study Design Multicenter retrospective cohort study. Setting & Participants Adults undergoing percutaneous native kidney biopsy at two high volume centers in Japan (January 2020 to December 2024) were included (n=458). Open or lateral decubitus biopsies and cases with undocumented pass counts were excluded. Exposure Number of needle passes. Outcomes Major bleeding (transfusion, bladder irrigation, interventional radiology, surgical hemostasis, or death) and next-day hemoglobin decline. Analytical Approach Major bleeding was evaluated using Firth penalized logistic regression (unadjusted and eGFR adjusted). Hemoglobin decline was evaluated using linear regression with a sensitivity analysis adjusting for baseline hemoglobin. Results The median number of needle passes was 5 (IQR, 4–6). Glomerular adequacy (≥10 glomeruli) was achieved in 94.5%, with a median of 30 glomeruli (IQR, 17–52). Major bleeding occurred in 7 patients (1.5%), including transfusion in 3 (0.7%), bladder irrigation in 3 (0.7%), and interventional radiology in 1 (0.2%); no surgical hemostasis or deaths occurred. Needle-pass number was not significantly associated with major bleeding (OR per pass, 1.23; 95% CI, 0.81–1.65; p=0.29) or after adjustment for eGFR (OR per pass, 1.14; 95% CI, 0.77–1.53; p=0.46). Needle-pass number was not significantly associated with hemoglobin decline (β, −0.028 g/dL per pass; 95% CI, −0.065 to 0.009; p=0.14), with consistent results in sensitivity analysis. Limitations Major bleeding events were few, limiting precision; the retrospective two-center design may limit generalizability and introduce bias. Conclusions In this cohort, needle pass number was not significantly associated with major bleeding or next-day hemoglobin decline. These findings support performing additional passes when needed to obtain adequate tissue while considering baseline bleeding risk. Plain-Language Summary Kidney biopsy is essential for diagnosing many kidney diseases, yet bleeding remains the most important complication. To obtain enough glomeruli for accurate interpretation, clinicians may take several tissue samples ("needle passes"). We studied 458 adults who underwent percutaneous native kidney biopsy at two high-volume hospitals in Japan between 2020 and 2024. The median number of passes was 5, producing a median of 30 glomeruli and adequate samples (at least 10 glomeruli) in 95% of biopsies. Major bleeding was uncommon (7 patients, 1.5%) and required transfusion, bladder irrigation, or radiology-based hemostasis; no one required surgery or died. A higher number of passes was not associated with major bleeding or with next-day hemoglobin decline. These results support performing additional passes when needed to secure adequate tissue, while carefully considering baseline bleeding risk, especially in patients with reduced kidney function.