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OASIS Manual · For everyone

OASIS Glossary

Common abbreviations, terms, and acronyms used throughout the OASIS-E2 spec — CMS-speak, billing-speak, and clinical-speak, defined in plain English.

By Reza Djangi, OTR/L·7 min read·Aligned with OASIS-E2 v1.00.0

CMS source

OASIS-E2 Guidance Manual · Verified 2026-10-16

TL;DR

OASIS picks up a lot of shorthand. CMS-speak, billing-speak, and clinical-speak all collide on the same form, and a clinician new to home health is trying to keep track of three vocabularies at once. This page is the cheat sheet — short definitions for the abbreviations that show up on the rest of this manual.

Terms

  • BIMS — Brief Interview for Mental Status. The Section C interview (C0200–C0400) on repetition, temporal orientation and recall, totaled in C0500 (00–15, or 99 if the patient couldn't complete it). C0100 is its gateway: if the patient is rarely or never understood, you skip the BIMS and go to C1310.
  • CASPER — Certification and Survey Provider Enhanced Reports. A legacy CMS reporting system. The OASIS-E2 manual's glossary says iQIES replaces it, so OASIS validation and quality reports now come from iQIES.
  • CMS — Centers for Medicare & Medicaid Services. The federal agency that defines OASIS, sets payment rules (HH PPS, PDGM), and sets the survey rules. The surveys themselves run through the state survey process.
  • CoP — Conditions of Participation. The federal regulations at 42 CFR 484 that home health agencies must meet to be Medicare-certified. The comprehensive assessment requirement (484.55) lives here.
  • dash response (—) — The entry that means no information is available. Only some items allow it, and CMS expects dash use to be a rare occurrence. Different from NA, and different from a skipped item.
  • Discharge — The OASIS timepoint at the end of a patient's home health episode for any reason other than transfer to an inpatient facility or death at home. RFA 09. Completed within 2 calendar days of the discharge date. Drives outcome quality measures.
  • GG items — The Section GG self-care and mobility items, scored on a 6-point scale (06 Independent through 01 Dependent) plus four "activity not attempted" codes. Collected at SOC/ROC and Discharge, and several at Follow-up, for outcome measurement.
  • HARP — In practice, the CMS sign-in you use to get into iQIES. (The CMS documents this manual cites don't cover sign-in.) Access to iQIES itself is managed by your organization's iQIES Security Officer.
  • HH — Home Health. The Medicare benefit category covered under 42 CFR 484 and reimbursed via HH PPS.
  • HHA — Home Health Agency. A Medicare-certified provider that delivers skilled home health services.
  • HHCAHPS — Home Health Consumer Assessment of Healthcare Providers and Systems. The patient experience survey whose results feed into the public Care Compare ratings.
  • HH PPS — Home Health Prospective Payment System. The CMS payment framework for home health, currently driven by PDGM groupings calculated from OASIS and claim data.
  • HH-VBP — Home Health Value-Based Purchasing. The CMS performance program that adjusts agency payment based on quality measure performance, including OASIS-derived measures.
  • HHRG — Home Health Resource Group. The case-mix grouping used under the legacy episode-based payment system. Replaced by PDGM in 2020 and is no longer used for payment, but still appears in older documentation.
  • HIPPS — Health Insurance Prospective Payment System code. The 5-character code on home health claims that encodes the PDGM grouping for billing.
  • iQIES — Internet Quality Improvement and Evaluation System. The CMS system agencies submit OASIS records to and read their validation and quality reports in. CMS's glossary says it replaces the legacy QIES, CASPER and ASPEN systems. In practice you sign in through HARP.
  • M0090 — Date Assessment Completed. The single most consequential date on an OASIS — anchors completion-window checks, the 30-day transmission clock, and the audit trail.
  • M0100 — Reason for Assessment (RFA). The OASIS item that identifies the type of assessment (SOC, ROC, Recert, Transfer, Discharge, etc.). Drives which items must be completed and how the record is processed.
  • NA — Not Applicable. A response some OASIS items offer for when the question doesn't apply to the patient's situation. Only valid where the item lists it, and CMS asks agencies to minimize its use. Different from a dash and different from a skipped item.
  • NOA — Notice of Admission. The 5-day initial billing notification under PDGM that tells the Medicare contractor a home health episode has started. Replaced the legacy RAP in 2022.
  • OASIS — Outcome and Assessment Information Set. The CMS-mandated comprehensive assessment data set used in home health to drive payment, quality measurement, and care planning.
  • OASIS-E2 — The OASIS version effective April 1, 2026. Compared with OASIS-E1 it removes O0350 (COVID-19 vaccination), replaces A1250 with A1255 (Transportation, now SOC/ROC only) and M0069 with A0810 (Sex), adds B0200, B1000 and A1110 to the ROC time point, and changes the J1900 responses.
  • OBQI — Outcome-Based Quality Improvement. The legacy CMS framework for using OASIS outcome data to drive agency quality improvement. Largely subsumed by current quality measure programs.
  • OBQM — Outcome-Based Quality Monitoring. The legacy companion to OBQI focused on adverse event monitoring. Most active reporting now runs through the quality measure reports in iQIES.
  • PBQI — Process-Based Quality Improvement. The process-measure complement to OBQI in the older OASIS quality framework. Mostly historical at this point.
  • PDGM — Patient-Driven Groupings Model. The current home health payment model, effective January 2020. Uses OASIS items, principal diagnosis, comorbidities, admission source, and timing to assign each 30-day period to one of 432 case-mix groups.
  • PHQ-2 / PHQ-9 — Patient Health Questionnaire (2-item screen and 9-item full instrument). Section D depression screen on OASIS. The first two questions act as the gateway: if both frequency answers are 0 or 1, or the patient gives no response to both, the interview ends; otherwise the remaining seven are asked.
  • QIES ASAP — Quality Improvement Evaluation System Assessment Submission and Processing. The legacy CMS submission system for OASIS, replaced by iQIES.
  • QM — Quality Measure. CMS-defined metrics calculated from OASIS, claims, and HHCAHPS data, published on Care Compare and used in HH-VBP scoring.
  • RAP — Request for Anticipated Payment. The legacy initial billing under HH PPS. Eliminated in 2022 and replaced by the NOA. Still appears in older training materials.
  • Recert — Recertification. The OASIS timepoint completed in the last 5 days of a 60-day cert when the patient continues home health services. RFA 04.
  • RFA — Reason for Assessment. The M0100 value identifying the type of OASIS being submitted. See the RFA Codes page for the full list.
  • ROC — Resumption of Care. The OASIS timepoint required when a patient returns to the agency after a 24+ hour inpatient stay during an active cert. RFA 03. Has a 2-day completion window.
  • SOC — Start of Care. The OASIS timepoint at home health admission. RFA 01. Anchors the 60-day cert period and has a 5-day completion window.
  • Transfer — The OASIS timepoint when a patient is admitted to an inpatient facility for 24+ hours during an active cert. RFA 06 if the agency expects the patient back (or isn't sure), RFA 07 if it doesn't and discharges the patient.