Your doctor should:

Send bills separately from medical reports. Billings go directly to:
Department of Labor and Industries
P.O. Box 44269
Olympia, WA 98504-4269
(Please attach a copy of the report for which you are billing L&I.)
Know that pre-authorization is still needed for outpatient surgery.
Fill out and sign a Time-Loss Notification form at least once a month if the patient is unable to work.
Seek a consultation from a medical doctor of his/her choice in a similar field of medicine, if the worker has missed more than 120 days of work.