The Value Set Authority Center (VSAC) currently serves as the authority and central repository for the official versions of value sets that support Meaningful Use 2014 Clinical Quality Measures (CQMs). The VSAC provides search, retrieval and download capabilities through a Web interface and APIs.
The VSAC will maintain and update the value sets consistent with the overall process for maintaining and updating the 2014 CQMs themselves. Through the VSAC, NLM draws upon the UMLS Metathesaurus and its responsibility as the central coordinating body for clinical terminology standards within the Department of Health and Human Services (HHS) to assure the on-going validity and accuracy of the value sets.
In the future, the VSAC will provide authoring tools for users to create value sets.

Value sets are lists of specific values (terms and their codes) derived from single or multiple standard vocabularies used to define clinical concepts (e.g. patients with diabetes, clinical visit, reportable diseases) used in clinical quality measures and to support effective health information exchange. Although there are many uses for value sets, a primary purpose of the value sets currently represented in the NLM VSAC is to support the 2014 Clinical Quality Measures prescribed for Meaningful Use of Electronic Health Records. Most of the value sets are therefore used to define the patient populations that should be included in the denominators and in the numerators when computing a clinical quality measure.

Once you have a UMLS License, you may log into the Value Set Authority Center (VSAC). Using the filters within the VSAC Web application, you can currently search, view and download specific value sets. You can search by text words, or you can limit your search to specific 2014 Clinical Quality Measures and unique identifiers. You can also retrieve all of the value sets associated with subsets of the 2014 Clinical Quality Measures, such as all Eligible Professional (EP) or all Eligible Hospital (EH) measures.

NLM has implemented the Sharing Value Sets (SVS) Technical Framework (PDF). Alternatively, users may wish to use a Common Terminology Services 2 (CTS2) based service maintained by Mayo Clinic to access NLM VSAC Value Set data.

According to the Centers for Medicare and Medicaid Services, "Clinical Quality Measures, or CQMs, are tools that help us measure and track the quality of healthcare services provided by physicians, nurses, hospitals and others in our health care system. These measures use a wide variety of data that are associated with a provider's ability to deliver high-quality care or relate to long term goals for health care quality. Many factors are included in CQMs such as health outcomes, processes and systems in place at a facility, patient perceptions, and treatments provided."

The Centers for Medicare and Medicaid Services (CMS) provide the official source for clinical quality measures that are required for Eligible Professionals (EH) and Eligible Hospitals (EH) to meet Meaningful Use (MU).
Additionally, the Agency for Healthcare Research and Quality (AHRQ) offers the United States Health Information Knowledgebase (USHIK) as an authoritative one-stop shop for public access to Meaningful Use quality measure components. The USHIK provides technical specifications for the 2014 Clinical Quality Measures including their descriptions, computation logic, data elements, context, version comparisons, and value sets. USHIK provides Measures and value sets in Excel, PDF and XML.

Please note: A free Unified Medical Language System® Metathesaurus License, available from NLM, is required when you use USHIK to

• access NLM Value Set Authority Center resources.
• view and/or download MU Value Sets, such as those including CPT® codes or SNOMED CT® codes.

Access to the Value Set Authority Center for viewing and/or downloading value sets, such as those including CPT® or SNOMED CT® codes, requires a free Unified Medical Language System® Metathesaurus License. Please note it may take 1-5 business days to obtain a license.
After your license has been approved, go to the VSAC application and click 'Sign In' with your UMLS username and password to begin using the VSAC.

The VSAC API offers a REST service to obtain CAS Ticket Granting Tickets (TGT) and Service Tickets. See the JASIG REST API documentation for more details on obtaining Ticket Granting Tickets and Service Tickets.
Broadly, in order to make API calls, do the following:

1. Obtain a TGT using your UMLS username and password by making a POST request to https://vsac.nlm.nih.gov/vsac/ws/Ticket. The TGT can be re-used to make calls to obtain single-use service tickets and is good for 8 hours.
2. Use your TGT to make a POST request for a single-use service ticket at the URL https://vsac.nlm.nih.gov/vsac/ws/Ticket/<TicketGrantingTicket>. Specify the URL http://umlsks.nlm.nih.gov as the service in the POST request. Each service ticket is good for 5 minutes but expires after one call.
3. Use your service tickets to make GET requests as specified in the methods below.

1. RetrieveValueSet

   RetrieveValueSet takes a Value Set Object Identifier (id) as a parameter. The Value Set Repository returns an expanded value set in XML format. It does not return any metadata (e.g., CQM metadata) associated with a measure.
   Example: https://vsac.nlm.nih.gov/vsac/ws/RetrieveValueSet?id=1.3.6.1.4.1.33895.1.3.0.31&ticket=<ServiceTicket>

2. RetrieveMultipleValueSets

   RetrieveMultipleValueSets not only returns an expanded value set, but also returns all metadata associated with the value set(s) such as a CQM or other higher level construct, as well as associated metadata. RetrieveMultipleValueSets can take one the following as parameters:

   • OID
     

     For use if you already know the object identifier for a value set. The OID parameter returns, in XML format, every expanded value set contained within this OID (including all terms, codes and code systems for each value set) along with the metadata for the each value set.
     Example:
     https://vsac.nlm.nih.gov/vsac/ws/RetrieveMultipleValueSets?id=1.3.6.1.4.1.33895.1.3.0.31&ticket=<ServiceTicket>

   • CMS eMeasure Identifier
     

     Use this to retrieve all value sets for a given CMS eMeasure ID. The returned XML contains every expanded value set for the eCQM (including all terms, codes and code systems for each value set) along with the metadata for the each value set.
     Example:
     https://vsac.nlm.nih.gov/vsac/ws/RetrieveMultipleValueSets?cmsemeasureid=CMS100v1&ticket=<ServiceTicket>

   • NQF Number
     

     Use this if you want to retrieve all value sets that support a particular National Quality Forum endorsed clinical quality measure. The returned XML contains every expanded value set contained within this NQFNumber (including all terms, codes and code systems for each value set) along with the metadata for the each value set.
     Example:
     https://vsac.nlm.nih.gov/vsac/ws/RetrieveMultipleValueSets?NQFNumber=0002&ticket=<ServiceTicket>

   • Measure ID
     

     Use this to retrieve value sets that support a given ID assigned by the Measure Authoring Tool (MAT).
     Example:
     https://vsac.nlm.nih.gov/vsac/ws/RetrieveMultipleValueSets?measureid=146&ticket=<ServiceTicket>

The VSAC Web browser provides a way to query, browse and filter the Value Set Repository. This is useful for an overall view of the value sets and their metadata. The VSAC Web browser application also allows you to download value sets in both XML format and in Excel spreadsheets.
Use the filters and your search terms to narrow your result set.

1. Query

   All Value Sets in the VSAC repository are automatically displayed when you first visit the "Search Value Sets"page. You can enter search terms directly into the Query box to narrow the result set. For example, you can type the term 'heart' and click the "Search" button to retrieve all value sets that contain the word 'heart' in a value set name, value set member, or in a term that is algorithmically mapped to the word 'heart'. You can also search by a specific object identifier (OID) that corresponds to one value set or a grouping of value sets.

2. Filters

   Use the Filters (on the left side of the interface) to refine your value set retrieval results by CMS eMeasure/NQF Number, Quality Data Model Category, Value Set Developer, or Meaningful Use Measures. Click the "Select" bar under the filter category you need, and select the appropriate check boxes for the value sets you are trying to retrieve. In order to apply your chosen filters, be sure to click the "Apply Filters"" button.
   Clicking on the "Clear Filters" button will clear all the filters you have selected and re-execute the most recently performed search with no filters.

3. Search Results and Value Set Details display

   The Search Results initially displays all value sets contained within the repository. After you have entered query terms, or codes, and applied your desired filters, the Search Results table displays the value sets retrieved by your search. The top right corner of the Search Result table displays the total number of retrieved value sets. There is also a check box column for selecting individual value sets of interest. Clicking on the column headings allows sorting entries alphanumerically.
   

4. Downloading Search Results
   XML: To download individual value sets, along with all terms and codes, in XML format, use the check boxes to select the value sets and click on one of the Download links above or below the Search Results table. Excel: Retrieved Value Sets (no value set member codes). Click the Export Search Results link to download search results in Excel format. The downloaded Excel workbook contains two worksheets, one with the information about your query terms and filters, and the other worksheet contains a summary of your retrieved value sets. This Excel spreadsheet does not contain the terms and codes for each value set. Excel: Fully Expanded Selected Value Sets, including member codes.
First, select an OID to view the value set members in the Value Set Details tab. Then, click the Export Value Set Results link to download an Excel spreadsheet containing your selected OID's value set's members.

View each row in Search Results

Clicking on any row highlights it. Click the View link at the top of the Search Results table to view a very brief summary for your highlighted value set.

Value Set Details View

To display value set details for one specific value set within your Search Results table, click on the OID link for that value set. The resulting Value Set Details view displays the following panels:

• Value Set Members: Lists the individual codes, terms (descriptors), code system, and code system version. You can use the text boxes at the top of each column to refine your search, and you can click the Export Value Set Results link to download an Excel spreadsheet containing a list of the value set's members.
• Metadata: Lists information for your selected value set, including the value set name, OID, type, and developer.
• Measure: Lists Measure information, if your selected value set contributes to one or more Measures.
• Member Of: Lists the parent (Grouping) value set, if your selected value set is a member of a grouping.
• Grouping: If your selected value set contains a grouping of multiple value sets, this panel lists each value set name and OID contained within the parent value set you have selected.