The Question · Hospital · Medicare Advantage
Medicare Advantage must follow the two-midnight benchmark. Most downgrades are never tested against it.
Since January 2024, MA plans must apply the same inpatient admission criteria as Original Medicare. Since January 2026, they can reopen an approved inpatient admission only for obvious error or fraud. Here is what the rules say, where downgrades happen, and how to argue them.
By ASP-RCM Editorial, Healthcare RCM Practice · Updated
The question we asked on LinkedIn
Medicare Advantage plans must follow the two-midnight benchmark since 2024. When a plan downgrades your inpatient stay, does your team argue screening criteria or cite 42 CFR 412.3?
Eligible beneficiaries in MA, 2026
35.2 million of 64.2 million with Parts A and B, per KFF
MA prior auth decisions, 2024
4.1 million denied (7.7%), up from 6.4% in 2023, per KFF from CMS Part C data
Of MA denials appealed, 2024
Nearly nine in ten denials were never challenged
Of MA appeals overturned, 2024
Fully or partially, per KFF. Appeals that get filed mostly win.
The rules that decide an MA inpatient stay
Quote these in every level-of-care dispute. They are federal regulation and CMS guidance, not plan policy.
| Rule | What it says | Why it matters to you |
|---|---|---|
| 42 CFR 412.3(d)(1), two-midnight benchmark | Inpatient is generally appropriate when the admitting physician expects care to cross two midnights, based on documented complex medical factors | MA plans must apply this criterion since January 1, 2024 (CMS-4201-F) |
| 42 CFR 412.3(d)(3), case-by-case exception | A stay expected under two midnights may still be inpatient on the admitting physician's clinical judgment, if the record supports it | Short stays are not automatically observation |
| Two-midnight presumption | A medical review instruction for Original Medicare audit contractors | MA plans do not have to follow it. They may still review stays before, during and after care |
| Internal coverage criteria, 42 CFR 422.101(b)(6) | Allowed only where Medicare criteria are not fully established, and must be evidence-based and publicly accessible | Ask the plan which criterion it used and where it is published |
| 42 CFR 422.138(c) | An approved prior or concurrent authorization cannot later be denied for lack of medical necessity, except on reopening | An approved admission is not open to a medical necessity re-review |
| CY 2026 rule (CMS-4208-F) | Plans may reopen an approved inpatient admission only for obvious error or fraud. Concurrent decisions are appealable organization determinations | Applies to coverage from January 1, 2026 |
Where an MA inpatient stay gets downgraded
CMS confirms MA plans may review medical necessity at three points. Each point needs a different response.
Before admission
Prior authorization for elective admissions. Send the physician's expected length of stay and the complex factors behind it.
During the stay
Concurrent review. A downgrade here is an organization determination, so notice and appeal rights apply.
After discharge
Claim review. If the admission was already approved, the plan can reopen it only for obvious error or fraud.
Appeal
Reconsideration with the 412.3 argument, the admission order, and documentation of the two-midnight expectation.
More hospitals are appealing, but most denials still stand unchallenged
Share of denied Medicare Advantage prior authorization requests that were appealed to the plan.
Source: KFF analysis of CMS Part C reporting data, January 28, 2026. Covers all prior authorization requests, not inpatient stays alone; CMS does not publish a service-level split.
Two ways to answer a downgrade
The difference is whether the argument is about a screening tool or about the regulation the plan is bound by.
Arguing the plan's screen
- Debating screening criteria scores line by line
- Accepting observation to avoid a fight
- Peer-to-peer with no admission order rationale in hand
- No log of which plans downgrade which DRGs
Arguing the rule
- Citing 42 CFR 412.3 and the CY 2024 rule in the first response
- Asking for the specific internal criterion and where it is published
- Physician note states the expected stay and the complex factors
- Flagging any post-approval reopening that is not error or fraud
How the MA inpatient rules got here
- Apr 2022
OIG finds 13% of sampled MA prior authorization denials met Medicare coverage rules.
- Apr 2023
CMS-4201-F finalized: MA plans must follow Original Medicare coverage criteria, including 412.3.
- Jan 1, 2024
CY 2024 rule in effect for MA coverage.
- Feb 6, 2024
CMS FAQ memo: benchmark applies to MA, presumption does not.
- Apr 2025
CMS-4208-F finalized: limits on reopening approved inpatient admissions.
- Jan 1, 2026
Reopening limit applies to MA coverage.
What to do with this on Monday
Separate the two denials
Track MA inpatient-to-observation changes apart from full denials. They have different appeal paths and different cash at stake.
Watch approved stays
Any recoupment on an admission the plan approved is worth a second look. Since 2026 the plan needs obvious error or fraud.
Check your contract
Federal rules set the floor for coverage. Your MA contract may add review timelines and appeal steps. Read both before you appeal.
Score your MA inpatient defense
Tick what is true for your hospital today.
MA plans are bound by the two-midnight benchmark, not the presumption. Document the expected stay, cite 412.3 in the first response, and treat every reopened approval as suspect. Most appeals that get filed win.
Questions operators ask next
Do Medicare Advantage plans have to follow the two-midnight rule?
They must follow the two-midnight benchmark in 42 CFR 412.3, which defines when inpatient admission is appropriate. CMS said in a February 2024 FAQ that MA plans do not have to follow the two-midnight presumption, which is an audit instruction for Original Medicare contractors. Plans can still review stays before, during and after care.
Can a Medicare Advantage plan reverse an approved inpatient admission?
Under 42 CFR 422.138(c), an approved prior or concurrent authorization cannot later be denied for lack of medical necessity, except through reopening. The CY 2026 MA rule, applying to coverage from January 1, 2026, limits reopening of an approved inpatient admission to obvious error or fraud.
Can MA plans use their own criteria for inpatient admissions?
Only where Medicare coverage criteria are not fully established. The internal criteria must be based on current evidence in widely used guidelines or clinical literature and be publicly accessible. Inpatient admission criteria are set in 42 CFR 412.3, so ask the plan which criterion it applied and where it is published.
Are Medicare Advantage denials worth appealing?
KFF found that in 2024 only 11.5% of denied MA prior authorization requests were appealed, and 80.7% of those appeals were fully or partially overturned. The data covers all services, not only inpatient stays, but it shows plans often reverse denials when challenged.
How many of your MA observation stays should have been inpatient?
Send us 90 days of Medicare Advantage inpatient denials and level-of-care changes. A senior hospital revenue cycle lead shows you which ones meet 412.3 and are worth appealing, in a free 30-minute call with a written gap report after.
Keep reading
Sources
- CMS, FAQs on coverage criteria and utilization management in CMS-4201-F, February 6, 2024 (via AHA)
- CMS, Contract Year 2026 MA and Part D final rule fact sheet, April 4, 2025
- eCFR, 42 CFR 412.3, admissions
- KFF, MA insurers made nearly 53 million prior authorization determinations in 2024, January 28, 2026
- KFF, Medicare Advantage in 2026: enrollment update and key trends
- HHS OIG, OEI-09-18-00260, MA prior authorization denials, April 2022
Checked November 4, 2026. Federal rules set minimum MA coverage standards; your payer contract may add review and appeal terms. General information, not legal advice.