Agreement given to the patient to read and sign before rendering a service if the participating physician thinks that it may be denied for payment because of medical necessity or limitation of liability by Medicare. The patient agrees to pay for the service. ABNs only apply if the patient is in the original Medicare program. They do not apply if the patient is in a Medicare managed care plan or private fee-for-service plan. May be referred to as an ABN-G (i.e., ABNs used by providers, physicians, practitioners, and suppliers). An ABN is also known as a waiver of liability agreement, responsibility statement , or notice of noncoverage. ABN-L refers to ABNs used when only laboratory services are being delivered. HHABN is an ABN used for home health services.