42 CFR § 424.27 - Requirements for comprehensive outpatient rehabilitation facility (CORF) services.
(a) Certification: Content.
(2) The services were furnished while the individual was under the care of a physician; and
(3) A written plan of treatment has been established and is reviewed periodically by a physician.
(b) Recertification -
(1) Timing. Recertification is required at least every 60 days for respiratory therapy services and every 90 days for physical therapy, occupational therapy, and speech-language pathology services based on review by a facility physician or the referring physician who, when appropriate, consults with the professional personnel who furnish the services.
(i) The plan is being followed;
(ii) The patient is making progress in attaining the rehabilitation goals; and,
(iii) The treatment is not having any harmful effect on the patient.