No, there is not a requirement to utilize services from any specific clearinghouse or billing agent. Providers have used an "in house" or internal solution if HIPAA 837 transactions are already set up within their organization.
Note: If the clearinghouse or billing agent will be used to bill, then the clearinghouse or billing agent must be enrolled with OWCP to receive 835 response files.
EDI Enrollment Template (For Billing Agent/Clearinghouse Only)