Overview

Local sets are a new construct for the creation of sets of concepts, similar to reference sets, but do not exist within a released or published edition or extension of SNOMED 

Creating Intensional Refset

To add an intensional refset follow these steps:

• Log into the tool (https://refset.ihtsdotools.org)
• Select the "Refset" tab
  
• Click on the "Add Refset" button available under the "Available" accordion.

• Fill out the "Add Refset" dialog and select "INTENSIONAL" as the Type.  The Definition must be in the format of the ECL (Expression Constraint Language)
  (e.g.) <<406455002 | Allergen class (substance) |
• See http://www.snomed.org/news-articles/expression-constraint-language for details about the ECL.
  
  
• Resulting subset will appear as follows with refset members populated based on the provided defintion.

Editing an Intensional Refset Definition

To edit an intensional refset follow these steps:

• Log into the tool (https://refset.ihtsdotools.org)
• Select the "Refset" tab
  
• Select the refset intended to be edited. Note that intensional refsets are indicated by the symbol.  On the right pane, the details of the refset are displayed, including the Definition editing which is pictured below.

• The Definition editing sub-panel has four actions: editing the definition(s), optimizing the definition(s), exporting definitions and importing definitions.
• Editing the Definition
  • Click on the pencil icon to bring up the "Definition Clauses" form

• • An additional clause can be entered into the text box.  Click the add button to add the clause to the list.
  • Click the negated clause if the components of this clause should be removed from the reference set.
  • Click the 'Recompute' button when the clauses are completely defined.  The refset members on the main pane will adjust accordingly.
• Optimizing the Definition
  • Click on the merging arrows icon to optimize the definition clauses.  This will remove any extraneous clauses that produce members which are completely contained within other clauses.  The refset members will remain the same.
• Exporting the Definition
  • Click on the down arrow icon to export the definition clauses to a file.
  • Choose the export format on the Export Definition form.  Click the Export button.
• Importing the Definition
  • Click on the up arrow icon to import definition clauses. When Import Definition form displays, select the file to be imported.  The file must be either an excel spreadsheet or a tab separated list containing the following headers and columns.

• • Note: Importing definition clause(s) will not augment any definition clauses already on the refset, rather it will replace the current definition after a confirm dialog.
• Adding Exclusions
  • Exclusions can be indicated from an intensional refset by clicking on the  icon on the row of a refset member.  
  • Exclusions are indicated with the red 'X' in a box icon.

• Adding Inclusions
  • Inclusions are added by clicking on the '+' icon at the far right of the Refset Members title (see above)
  • The Add Refset Member form will appear.
  • Click 'Add' next to the desired inclusion.
  • Inclusion members will then be indicated with the 'I' in a green box icon.  Concepts that are already members are indicated with the 'M' in a blue box icon.  Any exclusions are indicated with the 'X' in a red box icon.