38 C.F.R. § 8.24
Except as provided in § 8.22 , necessary transportation expenses incident to physical or mental examinations for insurance purposes at regional offices or medical facilities shall be furnished when the insured is ordered to report for examination at the specific request of the insurance activity concerned, or the Director of a regional office or of a medical facility. Such expenses will be borne by the United States and will be paid from the applicable appropriation of the Veterans Health Services and Research Administration. Transportation, meal and lodging requests in connection with reporting to and returning from the place of examination may be furnished the applicant, or the applicant may travel at his or her own expense and claim reimbursement for such travel on a mileage basis, provided prior authority has been given for the travel. Travel incident to such an examination by salaried employees of the Department of Veterans Affairs will be in accordance with the Federal Travel Regulations. If such an examination is made by a medical examiner on a fee basis, payment will be made at a fee not in excess of the schedule of fees in effect and approved by the Department of Veterans Affairs for medical and professional services in the State in which the examination is made. Where no approved State fee schedule is in effect or where a fee for the type of examination authorized is not listed in the approved State fee schedule in effect, such examinations will be furnished at a fee not in excess of that listed in the "Guide for Charges for Medical and Ancillary Services" of the Veterans Health Services and Research Administration in effect at the time the examination is authorized. If the particular examination is not covered by a schedule in effect and/or the said guide, a fee not in excess of what is reasonable and customarily charged in the community concerned may be allowed.
38 C.F.R. §8.24