CurrentAmbetter NevadaPolicy CP.MP.182

Short Inpatient Hospital Stay (PDF)

Defines medical necessity criteria for inpatient hospital stays lasting less than three midnights for non-Medicare Centene-affiliated health plans (excludes behavioral health and obstetrical delivery admissions) and states that stays of three midnights and beyond are medically necessary when supported by nationally-recognized clinical decision support tools.

Policy Summary

PayerAmbetter Nevada

PolicyShort Inpatient Hospital Stay (PDF)

Policy CodePolicy CP.MP.182

Change TypeAnnual review; revisions and clarifications (see changes)

Effective Date

Next Review Date

Key ActionDocument that inpatient admission decisions are supported by the nationally-recognized clinical decision support tool in use by the applicable plan; this support is required for several listed criteria (e.g., ICU admission, transfers, departure AMA).

SourceLink

POLICY UPDATE CHANGES

Updated criteria I.A. from CMS 2024 inpatient only to 2025 and updated the link.

Changed policy statement I. to state that an inpatient level of care for hospital stays of less than three midnights is medically necessary.

Added 'Acute hospital care at home' as criterion I.C.

Added note to policy to refer to MC.CP.MP.182 for Medicare criteria and specified 'non-Medicare' health plans.

7Listed indications that make <3 midnights medically necessary

3 midnightsInpatient length threshold considered routinely medically necessary

CMS Inpatient Only List year referenced

Coverage Summary

Overview: This policy (Policy Number CP.MP.182; Status: CURRENT) addresses medical necessity for short inpatient hospital stays. Coverage stance: covered_with_criteria. Subject: Short inpatient hospital stay medical necessity. Scope: defines medical necessity criteria for inpatient hospital stays of less than three midnights for non-Medicare Centene-affiliated health plans (excludes behavioral health and obstetrical delivery admissions) and states that stays of three midnights and beyond are medically necessary when supported by nationally-recognized clinical decision support tools. Key stats: Listed indications that make <3 midnights medically necessary: 7; Inpatient length threshold considered routinely medically necessary: 3 midnights; CMS Inpatient Only List year referenced: 2025.

Key thresholds and metadata

Length thresholdsLess than three midnights (short inpatient); three midnights and beyond (standard inpatient)

Policy number & titleCP.MP.182 — Short Inpatient Hospital Stay

PayerAmbetter Nevada / non‑Medicare health plans affiliated with Centene Corporation

Last review date02/25 (Date of Last Revision 02/25)

Next reviewNot specified

Scope summaryDefines medical necessity criteria for inpatient hospital stays lasting less than three midnights for non‑Medicare Centene‑affiliated health plans (excludes behavioral health and obstetrical delivery admissions); states stays of three midnights and beyond are medically necessary when supported by nationally‑recognized clinical decision support tools.

Medical Necessity Criteria

Medically necessary inpatient level of care for stays < three midnights

An inpatient level of care for hospital stays of less than three midnights is medically necessary when meeting ONE of the following indications:

Inpatient-only procedure (adults) or pediatric inpatient-only per InterQual: Admission is for a procedure on the CMS 2025 Inpatient Only List for members/enrollees age 18 years and over (addendum E here) or listed as a pediatric inpatient-only procedure in InterQual for members/enrollees under 18 years of age
ICU/NICU admission supported by clinical decision support tool: Admission to an intermediate or intensive care unit level of care (including neonatal intensive care unit (NICU)) is considered medically necessary per a nationally-recognized clinical decision support tool in use by the applicable plan
Must be supported by the nationally-recognized clinical decision support tool in use by the plan
Acute hospital care at home:

Provider Actions / Documentation Requirements

Documentation Required

Use of nationally-recognized clinical decision support tools

Document that inpatient admission decisions (both for stays under three midnights and for continued inpatient necessity) are supported by the nationally-recognized clinical decision support tool in use by the applicable plan. Include explicit citation in the medical record that the decision (e.g., for ICU/NICU admission, transfer justification, or departure AMA) was evaluated and met the plan’s clinical decision support criteria, and retain any tool outputs or assessments used to determine medical necessity.

Record which nationally-recognized clinical decision support tool was used and its version if available.
Include the specific criterion or trigger from the tool that justified the inpatient level of care.
Attach or summarize the tool output, score, or assessment in the patient’s chart.
For transfers or departures AMA, document the tool-based determination that the total inpatient stay met medical necessity (three midnights or more where applicable).

Coding / Referenced Resources

CMS Inpatient Only List referencedmixed

CMS Inpatient Only List 2025

Procedures designated by CMS as inpatient-only for members age 18 and over (link/reference)

Background

Background: Observation services provide short-term treatment, assessment, and reassessment to determine whether inpatient admission is required or the patient can be discharged; decisions usually occur within 24-48 hours and in rare cases exceed two days. The Centers for Medicare & Medicaid Services (CMS) maintains an Inpatient Only List which identifies procedures Medicare will pay only when performed in an inpatient setting and is updated annually; the policy references the CMS Inpatient Only List 2025. CMS also established the Acute Hospital Care at Home (Hospital at Home) program permitting eligible hospitals to provide certain acute-level services in the home with requirements including an in-person physician evaluation prior to starting, admission only from ED or inpatient beds, and at least daily physician rounding and medical team monitoring. This policy excludes behavioral health and obstetrical delivery admissions and applies to non-Medicare Centene-affiliated health plans; when applying Medicare-specific rules, reference to Medicare criteria and relevant NCDs/LCDs is noted.

Definitions

Medicare Determinations

Revision History

02/25/2025Annual review; references reviewed and updated.Latest

Updated criteria I.A. from CMS 2024 inpatient only to 2025 and updated the link.

09/24/2024Clarified language; policy statement revised.

Changed policy statement I. to state that an inpatient level of care for hospital stays of less than three midnights is medically necessary; added 'in use by the applicable plan' to criterion I.B; clarified transfer criterion I.F. to specify transfer from an inpatient stay with total length of three midnights or more; updated policy statement II. wording.

11/22Added criterion; background updated.

Policy Summary

PayerAmbetter Nevada

PolicyShort Inpatient Hospital Stay (PDF)

Policy CodePolicy CP.MP.182

Change TypeAnnual review; revisions and clarifications (see changes)

Effective Date

Next Review Date

SourceLink

On This Page

Admission to acute hospital care at home

Per CMS Acute Hospital Care at Home program requirements (in-person physician evaluation prior to starting; admission only from ED or inpatient beds; daily physician rounding and medical team monitoring)

Unexpected in-admission death: Unexpected death during the admission

Departure AMA from medically necessary inpatient stay: Departure against medical advice from a medically necessary (per a nationally-recognized clinical decision support tool) inpatient stay

Transfer from another inpatient facility with prior stay ≥3 midnights: Transferred from another inpatient facility, with a medically necessary (per a nationally-recognized clinical decision support tool) total length of stay of three midnights or more

Transfer must be from an inpatient stay and total stay must be three midnights or more

Election of hospice in lieu of continued hospital treatment: Election of hospice care in lieu of continued treatment in hospital

Stays of three midnights and beyond

Medically necessary when:

Stays of three midnights and beyond: Inpatient hospital stays lasting three midnights and beyond are medically necessary when supported by nationally-recognized clinical decision support tools

Documentation Required

Reference CMS inpatient-only list for adults

When using the criterion that admission is for a procedure on the CMS Inpatient Only List, document the member’s age and that the procedure appears on the CMS Inpatient Only List version referenced by the plan (CMS Inpatient Only List 2025). This criterion applies to members/enrollees age 18 years and over; for patients under 18, document if the procedure is listed as pediatric inpatient-only in InterQual.

State the patient’s age in the record and cite the CMS 2025 Inpatient Only List when applicable.
If the patient is under 18, document the InterQual pediatric inpatient-only designation if used.

Documentation Required

Acute Hospital Care at Home requirements

For admissions to Acute Hospital Care at Home, document compliance with CMS program requirements: an in-person physician evaluation was completed prior to starting hospital-at-home care; the patient was admitted only from an emergency department or an inpatient hospital bed; and the care plan includes at least daily physician rounding and ongoing medical team monitoring. Retain documentation of the initial in-person evaluation, admission source, and daily physician and team monitoring notes.

Document the in-person physician evaluation completed before initiating hospital-at-home.
Document the admission source as ED or inpatient hospital bed.
Document plans for and evidence of at least daily physician rounding and ongoing medical team monitoring.

Added 'Acute hospital care at home' as criterion I.C; background updated with no clinical significance.

08/23Applicability clarified; Medicare cross-reference added.

Added note to policy to refer to MC.CP.MP.182 for Medicare criteria and specified 'non-Medicare' health plans.

05/23Annual review; hyperlink and pediatric option added.

Updated hyperlink to CMS inpatient only list in Criteria I.A.; added option in I.A. for procedures listed as inpatient-only in InterQual for those under 18 years of age and noted CMS list applies to those 18 and over; minor rewording with no clinical significance.

04/24Annual review; wording and tool references updated.

Updated to policy description and added 'in use by the applicable plan' to criteria I.B; clarified transfer criterion I.F. to specify transfer is from an inpatient stay and total stay of three midnights or more.

02/20Policy development and initial structuring.

Policy developed and clarified that medical necessity criteria apply to day one and day two of an inpatient stay; added section II stating days 3 and beyond are medically necessary per nationally recognized clinical decision support tools.