April 3 2026
OASIS Answers
Categories: OASIS

New to Home Health Care? Learn What OASIS is and How to Use it

OASIS, the Outcome and Assessment Information Set, is a standardized group of data elements that Medicare-certified home health agencies incorporate into comprehensive patient assessments. Agencies submit OASIS data to the Centers for Medicare & Medicaid Services (CMS) for quality reporting, performance improvement and certain payment calculations.

OASIS-E2 is the current version of the assessment data set. It became effective April 1, 2026.

What Is OASIS Used For?

OASIS data gives CMS and home health agencies a standardized way to evaluate patient characteristics, care needs and outcomes. The data supports:

Home health quality measurement and reporting
Agency quality and performance-improvement efforts
Publicly reported quality measures
Risk adjustment for certain quality measures
Elements of Medicare home health payment calculations

OASIS is not a separate assessment. Home health agencies integrate its required data elements into the patient’s comprehensive assessment.

Which Patients Require an OASIS Assessment?

For patients beginning home health care with a start-of-care M0090 date on or after July 1, 2025, Medicare-certified home health agencies must collect and submit OASIS data for patients with any payer source unless an exemption applies.

CMS currently identifies exemptions that include:

Patients younger than 18
Patients receiving maternity services only
Patients receiving personal care, homemaker, housekeeping or chore services only
Certain patients receiving outpatient therapy from a home health agency without a home health plan of care
Certain patients served through a loaned-employee arrangement
Patients receiving only one visit during a quality episode

Because applicability depends on the patient’s services and circumstances, agencies should consult the current CMS OASIS guidance when determining whether an assessment is required.

When Is OASIS Completed?

Depending on the patient’s home health stay, OASIS assessments may be required at:

Start of care
Resumption of care
Recertification
Other follow-up
Transfer to an inpatient facility
Discharge from home health
Death at home

Not every OASIS item is collected at every assessment timepoint.

Who Can Complete OASIS?

OASIS is completed as part of the comprehensive assessment by an eligible clinician under current CMS requirements and agency policy. The clinician must apply the guidance for the applicable assessment timepoint and accurately represent the patient’s status during the required assessment period.

Because discipline requirements and assessment conventions can vary by circumstance, clinicians should refer to the current OASIS-E2 Guidance Manual and CMS OASIS Questions and Answers.

What Changed With OASIS-E2?

OASIS-E2 became effective April 1, 2026. Changes from OASIS-E1 include revised and replaced items, changes to certain assessment timepoints, updated response language and the integration of current CMS questions and answers into the guidance.

Clinicians should use the current OASIS-E2 instruments, Guidance Manual and CMS Q&As rather than relying on materials created for earlier OASIS versions.

How to Start Learning OASIS-E2

Begin with the CMS OASIS-E2 Guidance Manual

Chapter 1 of the OASIS Guidance Manual explains OASIS requirements, conventions and assessment fundamentals. Chapter 3 provides item-specific coding guidance. CMS OASIS Q&As offer additional direction for applying the guidance to more complex situations.

Take introductory OASIS training

OnRamp to OASIS is a three-hour, on-demand introduction for clinicians who are new to home health or OASIS data collection. It explains foundational concepts, how OASIS data is used and which CMS resources clinicians need to understand.

Develop practical coding skills

Blueprint for OASIS Accuracy is a comprehensive two-day workshop focused on applying current CMS guidance to realistic patient scenarios. It can also serve as a preparatory review for clinicians pursuing COS-C certification.

Stay current with CMS updates

CMS periodically publishes new and revised OASIS guidance. The Quarterly OASIS Update helps clinicians understand recent changes and apply them in practice.

Use an item-organized reference

The 2026 INSTANT OASIS Answers Book organizes current CMS guidance by OASIS item for convenient reference during assessments, auditing, education and COS-C exam preparation.

Build Your OASIS Knowledge With Confidence

Whether you are new to home health, learning OASIS-E2 or preparing for the COS-C certification exam, OASIS Answers offers education and reference materials designed to strengthen data-collection accuracy.

Explore OASIS training and resources to find the right next step for you or your agency.

Reviewed August 2026. Readers should consult current CMS guidance and their organization’s policies when making patient-specific assessment decisions.