IntroductionThe use of an automated biopsy device and real-time ultrasound (current technology) for percutaneous renal biopsies (PRBs) has improved the likelihood of obtaining adequate tissue for diagnosis and has reduced the complications associated with renal biopsies. Our objective was to evaluate the efficacy and safety of the current PRB procedure and identify possible risk factors for the development of major complications.Material and methodsWe collected all native kidney PRBs performed with current technology in our institute from January 1998 to April 2008. Studied variables were collected from the patient's chart at the time of the biopsy.ResultsWe analyzed 623 (96.4%) of 646 renal biopsies performed with the current automated procedure guided by real-time ultrasound. Although the effectiveness was 97.6%, there were 110 complications. Fourteen (2.24%) of these complications were major: 9 cases of renal hematoma, 2 cases with macroscopic hematuria (which needed blood transfusion), 1 case of intestinal perforation (which required exploratory laparotomy), 1 nephrectomy and 1 case of a dissecting hematoma. The logistic regression analysis demonstrated the following risk factors for developing major complications: diastolic blood pressure ≥ 90 mmHg, RR 7.6 (95% CI 1.35-43); platelet count ≤ 120×103/µl; RR 7.0 (95% CI 1.9-26.2); and blood urea nitrogen (BUN) ≥ 60 mg/dl, RR 9.27 (95% CI 2.8-30.7).ConclusionsThe observed efficacy and safety of the current technique in the present study were similar to observations in previous studies. Diastolic blood pressure ≥ 90 mmHg, platelets ≤ 120×103/µl and BUN ≥ 60 mg/dl were independent risk factors for the development of major complications following PRB.