Request:
Specifically, a consultation service is distinguished from other evaluation and management (E/M) visits because it is provided by a physician or qualified nonphysician practitioner (NPP)
whose opinion or advice regarding evaluation and/or management of a specific problem is requested by another physician or other appropriate source.
Render:
A request for a consultation from an appropriate source and
the need for consultation (i.e., the reason for a consultation service)
shall be documented by the consultant in the patient's medical record and included in the requesting physician or qualified NPP's plan of care in the patient's medical record
Report:
After the consultation is provided, the consultant shall prepare a written report of his/her findings and recommendations, which shall be provided to the referring physician.
http://www.cms.hhs.gov/MLNMattersArticles/downloads/mm4215.pdf
Also...30.6.10
http://www.cms.hhs.gov/manuals/downloads/clm104c12.pdf
Below is a clinical example-
99255 requires a comprehensive history, comprehensive exam and MDM of high complexity
http://emuniversity.com/ClinicalExample99245.html
Now...there are other factors that can be considered. Consultations may be billed based on time if the counseling/coordination of care constitutes more than 50 percent of the face-to-face encounter between the physician or qualified NPP and the patient.
Also...as for sharing the information with the requesting provider...
Consultation Report
A written report shall be furnished to the requesting physician or qualified NPP.
In an emergency department or an inpatient or outpatient setting in which the medical record is shared between the referring physician or qualified NPP and the consultant, the request may be documented as part of a plan written in the requesting physician or qualified NPP's progress note, an order in the medical record, or a specific written request for the consultation. In these settings, the report may consist of an appropriate entry in the common medical record.
In an office setting, the documentation requirement may be met by a specific written request for the consultation from the requesting physician or qualified NPP or if the consultant's records show a specific reference to the request. In this setting, the consultation report is a separate document communicated to the requesting physician or qualified NPP.
In a large group practice, e.g., an academic department or a large multi-specialty group, in which there is often a shared medical record, it is acceptable to include the consultant's report in the medical record documentation and not require a separate letter from the consulting physician or qualified NPP to the requesting physician or qualified NPP. The written request and the consultation evaluation, findings and recommendations shall be available in the consultation report.
This can seem overwhelming but the links provided should answer most of your questions. Hope this helps~