Outpatient versus inpatient renal biopsy: a retrospective study

There is a growing interest in the safety and efficacy of percutaneous kidney biopsy for outpatients in Taiwan. We conducted a retrospective study for patients receiving the biopsy in 2002 and 2003. Complication and mortality associated with the biopsy were compared between 147 inpatients and 183 outpatients who had been judged to need no hospitalization. All biopsies were performed using the ultrasound guidance and an automated spring-loaded biopsy device.

There were no death and no significant difference in complication rates between the two groups. No delayed gross hematuria, delayed pain, fever or biopsy site bleeding developed in outpatients, who were followed-up by telephone contacts for 1 - 5 days after they had been discharged. Both outpatients and inpatients with hematoma were younger than those without (p < 0.05). Template bleeding time was longer for inpatients with hematuria compared with inpatients without (12.0 vs. 5.8 minutes in average, p = 0.036), but not for outpatients (4.5 vs. 6.0 minutes in average, p = 0.282). There were moderate differences in platelet count between outpatients with hematuria and those without (p = 0.057), and in serum creatinine between inpatients with hematuria and those without (p = 0.069).

The outpatient renal biopsy appears to be equally as safe and efficient as the inpatient biopsy. However, we suggest checking template bleeding time and platelet count before biopsy for patients with clinical bleeding tendency, such as patients with a serum creatinine level over 4 mg/dl (approaching CKD stages IV, V) due to a higher risk of prolonged bleeding time. Outpatient biopsy with a 6-hour inpatient observation can be considered as a medically adequate procedure.