Answer: CMS alludes to the HPI restriction in the E/M documentation guidelines. You won't, however, find this rule verbatim.
The guidelines directly address only two of the history elements - the review of systems (ROS) and the past, family and/or social history (PFSH). "The ROS and/or PFSH may be recorded by ancillary staff or on a form completed by the patient," according to the 1997 Documentation Guidelines for Evaluation and Management Services (page 8). The 1995 guidelines also include this directive on page 5.
Neither guidelines directly address staff members performing the HPI, which is the third part of the history. Through the HPI omission, CMS implies that the FP, NPP, or other healthcare professional providing the E/M service must complete the HPI.