Will I owe the whole hospital bill if the admission is denied?

Not necessarily. In-network hospitals often can't bill you beyond normal cost-sharing for a denial caused by their own authorization or notification failure, and many appeal on their own. Ask the hospital what you owe while any appeal is pending.

What's the difference between inpatient and observation?

Observation is an outpatient status, even if you stay overnight in a hospital bed. It changes your cost-sharing and, for Medicare, can affect whether a later skilled nursing facility stay is covered.

Can the hospital appeal for me?

Yes. Hospitals and doctors can appeal level-of-care denials, and for urgent cases a treating doctor can request an expedited appeal on your behalf.

Does Medicare Advantage have to follow the two-midnight rule?

Since 2024, CMS rules require Medicare Advantage plans to follow Traditional Medicare's coverage criteria, including the two-midnight benchmark for inpatient admissions.

How to Appeal a Denied Inpatient Hospital Admission

By AppealFlow editorial•5 min read•Published October 2026

Insurers deny inpatient admissions when their reviewers decide the stay did not meet admission criteria, often downgrading it to observation or paying only part of the stay. You or the hospital can appeal with the physician's admission notes, the clinical reasons a shorter or outpatient stay was unsafe, and the criteria the plan used. Hospitals frequently appeal these on your behalf, so ask the billing office whether an appeal is already in progress before you file.

Why Do Insurers Deny Inpatient Stays?

Key Takeaway: The dispute is usually about level of care, not whether you needed treatment.

Most commercial insurers and Medicare Advantage plans review admissions using screening criteria such as InterQual or MCG. If the reviewer thinks your condition could have been managed as an outpatient or in observation, the plan may deny the inpatient claim or pay it at a lower rate. Denials can also come from missing notification: many plans require the hospital to notify them within a set time (often one business day) after an emergency admission.

Medical necessity: the plan says your symptoms didn't meet inpatient criteria.
Level of care: the plan agrees you needed care but says observation was enough.
Extra days: the plan approves admission but denies days it considers unnecessary.
Administrative: late notification or missing authorization.

What Is the Medicare Two-Midnight Rule?

Key Takeaway: Original Medicare and, since 2024, Medicare Advantage plans must follow it.

Under the two-midnight rule, Medicare generally considers an inpatient admission appropriate when the admitting doctor reasonably expects the patient to need hospital care spanning at least two midnights. CMS's 2024 Medicare Advantage rule (CMS-4201-F) requires MA plans to follow Traditional Medicare coverage criteria, including this rule, rather than stricter internal criteria. If you have Medicare Advantage and your stay was downgraded, that rule is worth citing. For how observation status affects you, read what hospital observation status means.

How Do I Appeal a Denied Admission?

Key Takeaway: Gather the clinical story from the hospital's records first.

Ask the hospital's billing or utilization review office whether they've already appealed; many hospitals do, and some contracts bar them from billing you while it's pending.
Request the denial letter, the criteria used, and the reviewer's credentials. Under ACA and ERISA claim rules you're entitled to the documents relevant to your claim at no cost.
Get the admitting physician's history and physical, progress notes, vital signs, labs and imaging from the first 24 to 48 hours.
Ask your doctor for a short letter explaining why discharge or observation was unsafe at the time, based on what was known then, not what happened later.
File the internal appeal before the deadline on your notice (often 180 days for commercial plans; for Medicare Advantage, generally 65 days from the notice). Use the medical necessity appeal generator to structure it.
If the internal appeal fails, request external review where your plan qualifies.

What If I'm Still in the Hospital?

Key Takeaway: Ask for an expedited review.

If coverage is being cut off while you're still admitted, ask for an expedited (urgent) appeal, which plans generally must decide within 72 hours. Medicare patients receive an Important Message from Medicare about discharge rights and can ask the Beneficiary and Family Centered Care Quality Improvement Organization (BFCC-QIO) for a fast review before leaving. See how to request an expedited appeal.

Related Guides

Frequently Asked Questions

Sources

Draft Your Appeal Letter

AppealFlow drafts a formal appeal letter from your denial details. Edit it, then download as PDF or Word. No account required.

Medical necessity appeal generator

Disclaimer: This article is for educational purposes only and does not constitute medical, legal, or financial advice. Plan terms, state laws, and federal rules vary and change. Check your plan documents and denial notice, and consider a licensed professional or your state consumer assistance program. See our full disclaimer.