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 Table of Contents

The 'Query Tool' is panel is where queries are constructed. 

3.1 Layout

  1. Panel Options allows users to (1) view the XML exchange between the client and the i2b2 server (if enabled) , (2) set options for the panel, and (3) resize the panel.
  2. Query Name Display shows the name of the current query. Users can also drop a previous query here to load it.
  3. Query Timing Selector enables users to select the appropriate timings for their query, including temporal queries.
  4. Query Groups are areas where users can drag and drop i2b2 items to build their queries. There are initially three Groups, but more can be added.
  5. Tool Bar contains buttons to run and clear queries. Its buttons also enable users to navigate the Groups.

3.2 Creating a Query

3.2.1 i2b2 Items for Querying

These items may be dragged into Query Groups to construct queries.



TermsTerms (also called concepts) are the words or phrases that make up the vocabularies and are the basic query items.


Term GroupsRelated terms are grouped into hierarchies. When a term group is used in a query, all terms in the group are searched for.


ModifiersModifiers are descriptors that can be attached to terms to make small changes to them. For example, a Diagnosis concept may be additionally described by Modifiers "Principal Diagnosis" or "Secondary diagnosis."


Modifier GroupsGroups of Modifiers, similar to Term Groups.


Previous QueriesPrevious Queries are queries that have been run before and are stored in the 'Previous Queries' panel.

Individual PatientsIf selected, a query can return a Patient Set. The Patient Set is stored with the query in the Previous Queries panel. The Patient Set can be expanded, and individual subjects dragged into query groups to be used in a new query.

Patient SetsIf selected, a query can return a Patient Set. The Patient Set is stored with the query in the Previous Queries panel and can be dragged into query groups to be used in a new query.

Encounter SetsIf selected, a query can return an Encounter Set. The Encounter Set is stored with the query in the Previous Queries panel and can be dragged into query groups to be used in a new query.

3.2.1 Operators and Order of Precedence

 i2b2 items are combined using Boolean operators AND and OR.

Items within each Group are first ORed together. The Groups are then ANDed together. 

Example 1 (AND): This query finds patients with Acute Myocardial Infarction AND Angina Pectoris.

Example 2 (OR): This query finds patients with Acute Myocardial Infarction OR Angina Pectoris.

Example 3 (AND of ORs): This query finds patients with (Acute Myocardial Infarction OR Angina Pectoris) AND who are male.

     *Note that the OR expression in the parentheses is evaluated first.

3.2.2 Constraints

Constraints are used to narrow down the search criteria to a particular time frame, number of occurrences or a specific value or range of values. In i2b2, there are several types of constraints that can be defined in the Query Tool view. 

  1. Group Constraints
    1. Date Constraint
      1. Setting Date Constraint for the entire Group


        Clicking on 'Dates' will display a dialog box in which a date range can be selected to restrict the occurrences of the items in the Group to within that range. Check one or both of the check boxes to indicate whether there is a begin date (From) or an end date (To) or both.


        Then type the date directly in the text box or click on the drop-down arrow to open the calendar below to select a date. This will set the date range for all items in this Group. 


      2. Setting Date Constraint on individual items.
        Sometimes only some items in the Group need date constraints or different items in one group require different date constraints. In this case,  right click on an item and select Set Date Constraint  to set the date constraint for that item specifically.

      3. How to tell if a date constraint has been applied.
        Once a date constraint is applied, Dates will now be underlined to indicate a date constraint has been set.


    2. Occurrence Constraint
    3. Exclusion
    4. Value Constraints (eg. labs)
    5. Numeric
    6. Categorical
    7. Text
    8. Flags (high, low, etc.)
  1. Modifier Value Constraints

3.2.3 Query Timing

  1. Independent
  2. Same Financial Encounter
  3. Same Observation
  4. Temporal Query

3.2.4 Reloading a Previous Query

3.2.5 Resetting the Query Tool

3.3 Running a Query

3.3.1 Run Query

3.3.2 Query Result Options

1) Patient Set
        2) Encounter Set
        3) Number of Patients
        4) Gender Patient Breakdown
        5) Vital Status Patient Breakdown
        6) Race Patient Breakdown
        7) Age Patient Breakdown
        8) Timeline
        9) Length of Stay Breakdown
        10) Top 20 Medications Breakdown
        12) Top 20 diagnoses Breakdown
        13) Inpatient and Outpatient Breakdown

3.3.3. Query Status

  1. Running
  2. Finished
  3. Queued
  4. Error

3.4 Example Queries

  i. Simple Query: "Finding patients with a diagnosis A or a diagnosis B or has lab test C."

  ii. Running a Previous Query

  iii. Temporal Query (Simple)

  iv.  How to find Patients with >1 diagnosis X OR >1 diagnosis Y  (Using nested queries)

Old Notes below (to be deleted):

    ii. Managing Groups

        1) Additional Groups
        2) Shifting Group Order
        3) Delete Groups

    iii. Specifying Constraints

        1) Date Constraints  (Panel-level and Term-level)
        2) Negation (Exclude)
        3) Occurrences

    iv. Value Constraints

(e.g. "Find patients who have a systolic blood pressure reading greater than 130 mm Hg")

    v. Modifiers

        1) What are they?
        2) Has Value Constraints like Labs
        3) How are they represented in Navigate/Find Terms
            - Modifier
            - Modifier Container

    vi. Query Timing

        1) Treat all groups independently (default)
        2) Select Groups occur in the same financial encounter
        3) Define sequence of events (Temporal Query)
            - Simple
            - Advanced
            - Some Concepts do not make sense here (Put them in the Population )

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