Transaction means the transmission of information between two parties to carry out financial or administrative activities related to health care. It includes the following types of information transmissions:
(1) Health care claims or equivalent encounter information.
(2) Health care payment and remittance advice.
(3) Coordination of benefits.
(4) Health care claim status.
(5) Enrollment and disenrollment in a health plan.
(6) Eligibility for a health plan.
(7) Health plan premium payments.
(8) Referral certification and authorization.
(9) First report of injury.
(10) Health claims attachments.
(11) Health care electronic funds transfers (EFT) and remittance advice.
(12) Other transactions that the Secretary may prescribe by regulation.
45 CFR § 160.103
Except as otherwise provided, the following definitions apply to this subchapter: