Medicare Denied Claim: Wrong Level of Care

What This Means

Medicare reviewed your claim and determined that you did not meet the medical criteria for the level of care that was billed. On your MSN or EOB this typically appears as CARC CO-50 (not deemed medical necessity) or CO-150 (information submitted does not support this level of service). This most commonly happens in two situations:

• Hospital stays: Your hospital stay was reclassified from inpatient to observation (outpatient) status, meaning Medicare Part A will not cover the stay.
• Skilled nursing facilities (SNFs): Medicare determined that you did not need the level of skilled care provided, or you did not meet the 3-day inpatient hospital stay requirement.

This denial can have a major financial impact, especially if it affects your eligibility for follow-up SNF care.

Why This Happens

• Your hospital stay was reclassified. Hospitals sometimes change a patient’s status from inpatient to observation after the fact, based on clinical criteria or utilization review. This can happen during your stay or even after discharge.
• You did not meet the usual 3-day inpatient requirement for SNF coverage. Original Medicare generally requires three consecutive hospital inpatient days, excluding the discharge day; observation days do not count. An approved ACO waiver may apply, and a Medicare Advantage plan may waive the stay requirement under 42 CFR 422.101(c)(2).
• Medicare determined a lower level of care was appropriate. For some conditions, Medicare may decide that outpatient treatment or home care would have been sufficient instead of a hospital or SNF stay.
• The documentation did not support the level of care. Even when the clinical situation clearly called for a higher level of care, the medical records submitted may not have conveyed the severity of your condition.

Should You Appeal?

What To Do Next

1. Determine the specific reason for the denial. Read your denial notice carefully. Was the issue your hospital status (inpatient vs. observation), your eligibility for SNF coverage, or the medical necessity of the level of care itself?
2. If inpatient status was changed to observation, check eligibility for QIO review. If you have Original Medicare, were formally admitted and then reclassified during the stay, and either lacked Part B or stayed at least three consecutive hospital days with fewer than three inpatient days, ask the QIO for fast review before hospital release. If you have already left, you can still request late QIO review, but the pending-review billing protection does not apply. The older retrospective route has a separate good-cause rule.
3. Ask your doctor for supporting documentation. Your doctor can write a letter explaining why the higher level of care was medically necessary for your condition. This is the most important part of your appeal.
4. Check whether you received a MOON notice. If you were in observation for more than 24 hours, the hospital was required to give you a Medicare Outpatient Observation Notice. This notice is important documentation for your appeal.
5. Contact your State Health Insurance Assistance Program (SHIP). SHIP counselors provide free help to Medicare beneficiaries and can guide you through the appeal process, especially for complicated level-of-care situations.

Sources

• CMS: Hospital Appeals — Change of Inpatient Status (Alexander v. Azar) — the implementing CMS rule for inpatient-to-observation appeals (forward-looking rights effective February 14, 2025; retrospective filing window closed January 2, 2026).
• Medicare.gov: Appealing a Denial of Part A Coverage from a Change in Status — beneficiary-facing guide to the new appeal rights.
• Medicare.gov: Skilled Nursing Facility Care Coverage — the 3-day inpatient stay rule for SNF Part A coverage.
• NOTICE Act of 2015 (Public Law 114-42) — federal law requiring hospitals to deliver a MOON notice when observation services exceed 24 hours.
• X12: Claim Adjustment Reason Codes (CARCs) — official definitions of CO-50 and CO-150.
• Center for Medicare Advocacy: Outpatient Observation Status — independent patient-advocacy explainer on observation status and its impact on SNF eligibility.
• KFF: Medicare Advantage Prior Authorization and Denial Data (Jan 2026) — overturn rates for appealed MA denials.

Frequently Asked Questions