Final answer:
Companies and payers in healthcare establish their own medical necessity guidelines and billing codes.
Step-by-step explanation:
In the field of healthcare, companies and other payers play a role in determining medical necessity and establishing guidelines for it. One of their roles is to establish their own medical necessity guidelines, which help determine what treatments and services are necessary and should be covered by insurance. These guidelines are based on factors such as evidence-based medicine, clinical expertise, and patient preferences. Companies and payers also establish billing codes to ensure proper reimbursement for medical services.