C.R.S. § 8-42-107

(I) (A) If the employee is not a state resident upon reaching maximum medical improvement, such physician shall, within twenty days after the determination of maximum medical improvement, determine whether the employee has sustained any permanent impairment. If the employee has sustained any permanent impairment, such physician shall conduct such tests as are required by the revised third edition of the "American Medical Association Guides to the Evaluation of Permanent Impairment" to determine such employee's medical impairment rating and shall transmit to the self-insured employer or insurer all test results and all relevant medical information.

(B) However, if the employee chooses not to have the authorized treating physician perform such tests, or if the information is not transmitted in a timely manner, the self-insured employer or insurer shall arrange and pay for the employee to return to Colorado for examination, testing, and rating, at the expense of the self-insured employer or insurer. If the employee refuses to return to Colorado for examination, no permanent disability benefits shall be awarded.

(C) The self-insured employer or insurer shall, within twenty days after receipt of the medical information described in sub-subparagraph (A) of this subparagraph (I), appoint a level II accredited physician to determine the employee's medical impairment rating. If the employee was treated by an authorized level II accredited physician in Colorado for the same injury for which a medical impairment rating is being sought, the self-insured employer or insurer shall request such physician to determine the claimant's medical impairment rating. At the same time as such rating is transmitted to the self-insured employer or insurer, the level II physician shall transmit a copy of the same to the authorized treating physician and the employee.

(D) If the employee, insurer, or self-insured employer disputes a medical impairment rating, including a finding that there is no medical impairment, made pursuant to sub-subparagraph (A) of this subparagraph (I), the parties to the dispute may select an independent medical examiner in accordance with section 8-42-107.2 to review the rating. The cost of such independent medical examination shall be borne by the requesting party. The finding of such independent medical examiner shall be overcome only by clear and convincing evidence. Any review by an independent medical examiner shall be based on the employee's written medical records only, without further examination, unless a party to the dispute requests that such review include a physical examination by the independent medical examiner. Except when the provisions of section 8-42-107.2 (5)(b) apply, the party requesting a physical examination shall pay all additional costs, including, if applicable, the reasonable cost of returning the employee to Colorado.

(II) If the employee is a state resident, such physician shall, within twenty days after the determination of maximum medical improvement, determine whether the employee has sustained any permanent impairment. If the employee has sustained any permanent impairment, such physician shall refer such employee to a level II accredited physician for a medical impairment rating, which shall be based on the revised third edition of the "American Medical Association Guides to the Evaluation of Permanent Impairment". If the referral is not timely made by the authorized treating physician, the insurer or self-insured employer shall refer the employee to a level II accredited physician within forty days after the determination of maximum medical improvement. If the employee, insurer, or self-insured employer disputes the finding regarding permanent medical impairment, including a finding that there is no permanent medical impairment, the parties to the dispute may select an independent medical examiner in accordance with section 8-42-107.2. The finding of any such independent medical examiner shall be overcome only by clear and convincing evidence.