The National Institutes of Health (NIH) previously issued a policy on the use of a single Institutional Review Board (IRB) for multi-site research. The policy is to establish the expectation that a single IRB (sIRB) of record will be used in the ethical review of non-exempt human subjects research protocols funded by the NIH that are carried out at more than one site in the United States.
The policy (http://grants.nih.gov/grants/guide/notice-files/NOT-OD-16-094.html) was to go into effect on May 25, 2017. NIH has now extended the effective date to September 25, 2017
Extension of Effective Date of NIH Policy on the Use of a Single Institutional Review
Board for Multi-Site Research: https://federalregister.gov/d/2016-30398