The early impacts of an attempt to standardize kidney procurement biopsy practices.

Procurement biopsies are routinely obtained in the United States to evaluate kidneys considered for transplantation, but some argue that they may contribute to kidney nonutilization. Historically, biopsy decisions have been left solely to the discretion of organ procurement organizations (OPOs) and transplant centers. In September 2022, an organ procurement and transplantation network (OPTN) policy designating donors meeting specific clinical criteria as "biopsy-required" went into effect. Using OPTN data from 1 year before and after policy implementation, we used causal inference methods to estimate the policy's impacts on biopsy practices and kidney utilization. The overall biopsy rate remained stable at 62%, rising from 90.6% to 95.8% (P < .001) among biopsy-required kidneys while falling from 49.1% to 43.4% (P < .001) among biopsy-optional kidneys. After adjusting for changing donor characteristics, the policy was associated with a 5% decline in the biopsy rate (adjusted risk ratio = 0.95; P = .007). The overall kidney nonuse rate rose from 27.2% to 28.7%. After accounting for changes in donor characteristics, the policy was not associated with elevated nonuse (adjusted risk ratio = 0.96, P = .06). Although most OPOs are now biopsying nearly all required kidneys, practices still vary widely regarding biopsy-optional kidneys. No correlation was found between OPO-level changes in adjusted biopsy and nonuse rates (ρ = 0.05, P = .70). The OPTN policy has partially standardized biopsy practices without harming kidney utilization.