OASIS-E1 is the version of the Outcome and Assessment Information Set (OASIS) that took effect on January 1, 2025, replacing OASIS-E for all Medicare-certified home health assessments with an M0090 (Date Assessment Completed) on or after that date. Unlike the sweeping OASIS-E update of 2023, OASIS-E1 is a deliberately small, maintenance-level revision: CMS removed two long-unused items, added one new COVID-19 vaccination item, trimmed the discharge goals from two functional (Section GG) items, and clarified the instructions for one mental-status item. Nothing about PDGM payment mechanics changed — but the GG revisions and the new vaccination measure quietly affect quality reporting and Home Health Value-Based Purchasing, which is where the money follows.
This guide breaks down exactly what changed, item by item, why the Section GG revision matters more than it looks, and what home health agencies should do to stay accurate under OASIS-E1. Every regulatory point below traces to CMS's own guidance so your clinical and coding teams can verify it directly.
What OASIS-E1 Is — and Why It's a Smaller Change Than OASIS-E
The jump from OASIS-D1 to OASIS-E on January 1, 2023 was one of the largest expansions of the data set in its history: it added standardized patient assessment data elements covering social determinants of health, cognitive function, and medication reconciliation. OASIS-E1 is the opposite in spirit — a targeted "cleanup" release that removes questions clinicians no longer needed to answer and aligns the instrument with quality measures finalized in rulemaking.
CMS documents the complete change set in the OASIS-E1 Guidance Manual, the authoritative reference every agency should adopt as its assessment standard. The practical headline: fewer items to complete, so most Start of Care and recertification assessments take slightly less time — with one new data-gathering task around vaccination status.
What Changed: Items Removed, Added, and Revised
Removed: M0110 (Episode Timing) and M2200 (Therapy Need)
CMS removed two items that had been effectively dormant since the Patient-Driven Groupings Model (PDGM) took effect in 2020: M0110 (Episode Timing) and M2200 (Therapy Need). Both were artifacts of the pre-PDGM Prospective Payment System, where therapy visit volume drove reimbursement. Under PDGM, therapy thresholds no longer influence payment, so neither item was being used in the Home Health Quality Reporting Program (HH QRP) or for other CMS purposes.
For agencies, this is a clean win: two fewer fields to complete on every applicable assessment, with zero downstream payment impact. If your EHR still surfaces these items after your OASIS-E1 upgrade, that is a software configuration issue to raise with your vendor, not a clinical one.
Added: O0350 (Patient's COVID-19 Vaccination Is Up to Date)
The single new item is O0350, which records whether the patient's COVID-19 vaccination is up to date. It is tied to the "COVID-19 Vaccine: Percent of Patients/Residents Who Are Up to Date" quality measure that CMS finalized in the CY 2024 Home Health Prospective Payment System final rule. Because O0350 feeds a publicly reported quality measure, accurate and complete responses matter for your agency's Care Compare profile — an incomplete or defaulted answer is a quality-data problem, not just a blank field.
This is the one place OASIS-E1 may add time rather than save it: confirming a patient's current vaccination status can require checking records or asking follow-up questions during the assessment.
Revised: GG0130 (Self-Care) and GG0170 (Mobility) — Discharge Goals Removed
CMS revised the two core Section GG functional items — GG0130 (Self-Care) and GG0170 (Mobility) — to remove the Discharge Goal columns. This change follows the removal of the "Application of Percent of Long-Term Care Patients With an Admission and Discharge Functional Assessment and a Care Plan" measure from the HH QRP, which the discharge-goal coding had supported.
Clinicians still code the admission (Start of Care/Resumption of Care) performance and the discharge performance for these functional items — they simply no longer set a coded numeric goal at admission. The functional scoring that drives PDGM's functional impairment level (low, medium, or high) is unchanged, which is why this revision needs a careful read: you are dropping a column, not changing how functional status is assessed or how it maps to payment.
Clarified: D0150 (Patient Mood Interview, PHQ-2 to -9)
Finally, CMS clarified the instructions for D0150 (Patient Mood Interview) — the PHQ-2 to -9 mental-status item — to reduce inconsistent coding. There is no new question here, just sharper guidance on how to conduct and record the interview. Agencies should update their clinician training and QA checklists to reflect the clarified instructions so mood coding stays consistent across your team.
Why the Section GG Change Matters More Than It Looks
On paper, "remove the discharge goal column" sounds like a formatting tweak. In practice, Section GG is one of the most consequential parts of the assessment, because GG functional data flows into three separate systems: PDGM case-mix (through the functional impairment level), the HH QRP quality measures, and Home Health Value-Based Purchasing (HHVBP), which adjusts your Medicare payments up or down based on quality performance.
That means a coding habit change in GG — even a subtractive one — is exactly the kind of transition where errors creep in. A clinician trained for two years to code an admission performance, an admission goal, and a discharge performance now codes only two of the three. The risk is not the missing goal; it is inconsistency in the performance items during the changeover. Because those performance scores affect both reimbursement and value-based payment, this is the item set most worth auditing after your OASIS-E1 go-live. A focused coding & OASIS review on a sample of post-transition assessments is the cheapest insurance against a scoring drift you won't otherwise see until quality scores publish months later.
The Rules That Did Not Change
It is just as important to know what OASIS-E1 left alone, so teams don't over-correct:
- PDGM payment mechanics are untouched. The five case-mix dimensions — admission source, timing, clinical grouping, functional impairment level, and comorbidity adjustment — work exactly as before. If you want that model in plain language, our PDGM guide walks through each dimension.
- Assessment timing rules are the same. The Start of Care comprehensive assessment must still be completed within 5 calendar days after the start of care, and the M0090 date governs which OASIS version applies.
- The primary-diagnosis-to-clinical-group logic is unchanged. An ICD-10-CM primary diagnosis that does not map to a valid clinical group still produces a "questionable encounter" that will not group for payment.
In other words, OASIS-E1 changes the form, not the financial engine behind it. The agencies most exposed to error are the ones that treat a small version change as no change at all and skip the clinician re-training.
What Home Health Agencies Should Do Now
1. Adopt the OASIS-E1 Guidance Manual as your standard and retire OASIS-E references in your policies and clinician job aids. 2. Re-train on the four touchpoints: dropping M0110/M2200, capturing O0350 accurately, coding GG0130/GG0170 without the discharge goal, and the clarified D0150 interview. 3. Confirm your EHR upgrade is complete — the removed items should no longer appear, and O0350 should be present and required. 4. Audit a post-go-live sample of Section GG coding and O0350 completeness before the data reaches quality reporting. Pairing that internal check with a formal clinical documentation review catches drift while it is still fixable. 5. Watch your Care Compare vaccination measure once O0350 data begins to report, and treat blanks or defaults as defects to correct upstream.
Handled well, OASIS-E1 is a low-risk, slightly-faster assessment. Handled carelessly, it becomes a quiet source of Section GG scoring drift that shows up as lost PDGM revenue and softer HHVBP performance — the exact place where accurate OASIS work protects the revenue cycle.
Frequently Asked Questions
When did OASIS-E1 take effect?
OASIS-E1 took effect on January 1, 2025. It applies to any OASIS assessment with an M0090 (Date Assessment Completed) on or after January 1, 2025; assessments completed before that date continued to use OASIS-E. The change set is documented in the CMS OASIS-E1 Guidance Manual.
What items were removed in OASIS-E1?
CMS removed two items: M0110 (Episode Timing) and M2200 (Therapy Need). Both had been unused for Medicare payment since PDGM began in 2020 and were no longer needed for the Home Health Quality Reporting Program. CMS also removed the Discharge Goal columns from the GG0130 (Self-Care) and GG0170 (Mobility) functional items.
Does OASIS-E1 change PDGM reimbursement?
No. OASIS-E1 does not change how PDGM pays. The five case-mix dimensions and the functional impairment scoring that influence payment are unchanged. The revision removes unused items, adds the O0350 COVID-19 vaccination item for quality reporting, and clarifies instructions — none of which alters the PDGM payment calculation itself.
What is the new O0350 item?
O0350 records whether the patient's COVID-19 vaccination is up to date. It supports a quality measure finalized in the CY 2024 Home Health PPS final rule and is publicly reported, so accurate completion affects your agency's Care Compare quality profile.
Medeoan's certified coders and OASIS reviewers assess assessments against the current OASIS-E1 guidance every day — validating Section GG scoring, O0350 completeness, and primary-diagnosis grouping so accuracy holds through the version change. If you want a second set of expert eyes on your post-transition OASIS work, our coding & OASIS review team can help.