20 C.F.R. § 702.408

In any case in which medical questions arise with respect to the appropriate diagnosis, extent, effect of, appropriate treatment, and the duration of any such care or treatment, for an injury covered by the Act, the Director, OWCP, through the district directors having jurisdiction, shall have the power to evaluate such questions by appointing one or more especially qualified physicians to examine the employee, or in the case of death to make such inquiry as may be appropriate to the facts and circumstances of the case. The physician or physicians, including appropriate consultants, should report their findings with respect to the questions raised as expeditiously as possible. Upon receipt of such report, action appropriate therewith shall be taken.