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ABN Medical Abbreviation: The Medicare Notice and Abnormal

Chart notes and nursingBillingFront officeReviewed 30 Oct 2026

The ABN medical abbreviation most often stands for Advance Beneficiary Notice of Noncoverage, a written notice that a clinic, lab or supplier gives a person with original Medicare before a service that Medicare may not pay for. In clinical notes and lab reports, lower case abn is also a common shortcut for abnormal.

Patients usually meet the notice at a front desk or lab check in, and medical assistants, billers and coding students learn it as part of front office work. This page explains what the notice does, when it is given, and how to tell it apart from the abnormal meaning.

At a glance

  • Stands for

    Advance Beneficiary Notice of Noncoverage
  • Other meanings

    Abnormal, as in abn lab or abn findings
  • Used in

    Original Medicare billing, clinics, labs, equipment suppliers
  • Where you see it

    Front desk, lab check in, billing records
  • Who signs

    The patient or their representative, before the service
  • Related terms

    CPT codes, EOB (explanation of benefits)

What the ABN medical abbreviation means at the front desk

An Advance Beneficiary Notice tells a person with original Medicare, before they receive an item or service, that the provider believes Medicare may not cover it in this case. Common reasons include a test done more often than coverage rules allow, or a service Medicare does not consider medically necessary for the stated diagnosis.

The notice gives the patient a chance to decide, with the facts in front of them, whether to go ahead. It names the service, explains why coverage may be denied, and gives space to choose an option and sign. A staff member should be able to answer questions about it before the patient signs.

The choices on the notice

The form usually lists options for the patient to pick from. In broad terms they are:

Typical options on an Advance Beneficiary Notice
ChoiceWhat it means in general
Receive the service and have it billed to MedicareMedicare reviews the claim; if it is denied, the patient may be responsible and can appeal
Receive the service without billing MedicareThe patient pays directly and no claim is sent, so no appeal is possible
Decline the serviceThe service is not done and nothing is billed for it

The exact wording on the form, and the rules behind it, are set by Medicare. A billing office can explain how the choice applies to a given visit.

A realistic ABN moment

At a lab check in: "Medicare may not pay for one of the tests on this order for the reason listed, so please review this ABN before we draw your blood." The staff member is giving notice that this test may not be paid by Medicare, so the patient can choose how to proceed.

In the chart, staff may then write a line such as "ABN signed, option 1 selected," so the billing team knows the notice was given and which choice was made.

ABN meaning abnormal in notes and results

In clinical writing, abn is a plain short form of abnormal. It shows up in lines like "abn LFTs," meaning abnormal liver function tests, or "abn gait," meaning an unusual way of walking. On some lab printouts a result may also be flagged H or L for high or low, which is a related idea.

The contrast with the Medicare notice is clear in context. Abnormal sits next to a test, finding or body part. The notice sits next to words like signed, given, Medicare, coverage or billing. The LFT and WNL pages show more result shorthand.

ABN abbreviation medical students should know

Medical assistant and billing students learn a few practical points about the notice: it must be given before the service, not after; it should name the specific item and give a real reason; and a blanket notice signed for every visit is not how it is meant to be used. Coders may also see a related claim modifier showing a notice is on file.

The chart notes and nursing section covers more of the shorthand that appears in front office and clinical records.

Coverage rules are specific to each plan and situation. The provider's billing office or Medicare itself can explain how a particular notice affects you.

Frequently asked questions

What does ABN mean in medical billing?

It means Advance Beneficiary Notice of Noncoverage. It is a notice given to people with original Medicare before a service that Medicare may not pay for.

Do I have to sign an ABN?

The notice asks you to choose an option and sign before the service. If you have questions or concerns, ask the staff to explain it, or contact the billing office before deciding.

What does abn mean on lab results?

In results and notes, abn is short for abnormal. It means a value or finding fell outside what is expected; whoever ordered the test can say what it means in your case.

Is an ABN the same as an EOB?

No. An ABN is given before a service to warn that coverage may be denied. An explanation of benefits comes from a plan after a claim to show how it was processed.