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OASIS-C1 Data Sets

Background

OASIS-C1 is the current version of the OASIS data set.  It was developed from OASIS-C to accommodate the transition to the ICD-10 diagnosis coding system, as well as and other important stakeholder concerns such as updating clinical concepts, and revised item wording and response categories to improve item clarity. The OASIS-C1 data item set was approved by the Office of Management and Budget (OMB) on February 6, 2014 and scheduled for implementation on October 1, 2014.  However, on April 1, 2014, the Protecting Access to Medicare Act of 2014 (PAMA) (Pub. L. No. 113-93) was enacted, which announced October 1, 2015 as the new compliance date.  Due to this delay, CMS had to ensure the collection and submission of OASIS data continued, until ICD-10 could be implemented.  Therefore, we have made interim changes to the OASIS-C1 data item set to allow use with ICD-9 until ICD-10 is adopted. 

The following is a summary of the changes:

OASIS-C1 / ICD-9 version:

  • A modified version of OASIS-C1 (referred to as “OASIS-C1/ ICD-9 version.”) was created. It  replaced the five OASIS-C1 items that use ICD-10 diagnosis codes (i.e. - M1011, M1017, M1021, M1023, M1025) with the corresponding ICD-9-CM based items from OASIS-C (i.e. – M1010, M1016, M1020, M1022, M1024). 
  • The OASIS-C1/ ICD-9 version underwent an “emergency” Paperwork Reduction Act review by OMB and was granted approval on October 10, 2014 for implementation on January 1, 2015.
  • The OASIS-C1/ICD-9 data set is required for all assessments completed on or after January 1, 2015 and until ICD-10 is implemented or until another disposition is made by CMS. 
  • The complete set of OASIS-C1/ICD-9 data items, as well as the subsets of OASIS-C1/ICD-9 items that are to be collected at each time point (Start of Care, Recertification, etc.) can be found in the Downloads section below. 
  • Detailed instructions for use of the OASIS-C1/ICD-9 data set can be found in OASIS-C1/ ICD-9 Guidance Manual, which is posted on the OASIS User Manuals page (see the link in the “Related Links” section below.)
  • If you have additional questions about completion of the OASIS-C1/ ICD-9 items, you can consult the OASIS Q&As using the "OASIS Q&As" link in the Related Links section below.
  • The OASIS-C1 / ICD-9 version data must be encoded and submitted to CMS using OASIS Data Specifications, version 2.11.n.  These can be accessed via the “OASIS Data Specifications” link in the “Related Links” section below.

OASIS-C1 / ICD-10 version:

  • The OASIS-C1 / ICD-10 version of the OASIS data set replaces the five ICD-9-CM-based items in the OASIS-C1 / ICD-9 data set (M1010, M1016, M1020, M1022, M1024) with the corresponding ICD-10 items (M1011, M1017, M1021, M1023, M1025).   A table showing the differences between the OASIS-C1 / ICD-9 and OASIS-C1 / ICD-10 versions is available below in the Downloads section.
  • The OASIS-C1 / ICD-10 version of the OASIS data set received Paperwork Reduction Act approval from OMB on May 29, 2015.
  • The OASIS-C1/ICD-10 data set is scheduled to be the version required for all assessments completed on or after October 1, 2015, when ICD-10 is scheduled to be implemented by CMS. 
  • The complete set of OASIS-C1/ICD-10 data items, as well as the subsets of OASIS-C1/ICD-10 items that are to be collected at each time point (Start of Care, Recertification, etc.) can be found in the Downloads section below. 
  • Detailed instructions for use of the OASIS-C1/ICD-10 data set can be found in OASIS-C1/ ICD-10 Guidance Manual, which is posted on the OASIS User Manuals page (see the link in the “Related Links” section below.)
  • If you have additional questions about completion of the OASIS-C1/ ICD-10 items, you can consult the OASIS Q&As using the "OASIS Q&As" link in the Related Links section below.
  • The OASIS-C1 / ICD-10 version data must be encoded and submitted to CMS using the OASIS Data Specifications, version 2.12.n.  These can be accessed via the “OASIS Data Specifications” link in the “Related Links” section below.

OASIS and Medicare Home Health PPS

The most current information about Home Health PPS and use of OASIS can be found on the Home Health PPS web page via the link in the “Related Links” section below.