Biobanks containing clinical specimens: defining characteristics, policies, and practices.

•We present survey data from 261 U.S. biobanks that store specimens from clinical sources.•There is tremendous variation in the sources, number and types of specimens stored.•Most biobanks use broad/global opt-in informed consent procedures.•We describe biobank policies on return of results and specimen ownership.•Legal/ethical regulations must accommodate a complex landscape of modern biobanking.