The components and criteria within a CDS rule should also be considered when designing or implementing the rules. Some of the additional aspects of these considerations have been described below.
Multi-Component CDS Rules
Multiple events, conditions, or actions may be associated with each CDS rule. For example, two separate actions defined in a medication allergy rule might be:
- Firstly to alert the user and;
- Secondly to suggest an alternative drug
Additional examples of complex rules, with multiple conditions and actions, are provided in the section 3.1.3. Rule Examples.
Criteria in CDS Conditions
Each CDS condition (or criterion) can be further subdivided into a "name-value" pair. The criterion name will typically map to a data element in the electronic health record, while the criterion value is compared with the data that populates this element in the patient's health record.
Criterion Name | Criterion Value |
---|---|
Pregnancy status | |
Drug prescribed | |
Hematocrit result |
Criteria Values
Some criteria may refer to the value of coded data elements, while others may refer to the value of non-coded data elements. When a criterion refers to a SNOMED CT encoded data element, the value may be a SNOMED CT Expression Constraint that defines the permitted subset of concepts that will satisfy this criteria.
Criterion Name | Criterion Value |
---|---|
Condition | |
Diagnosis | |
Procedure |
Criteria that refer to non-coded data elements may use operators that are valid for the given element's data type. For example, criterion that refer to numeric data elements may use standard mathematical operators to restrict the required value.
Criterion Name | Data Type | Operator | Value | Units |
---|---|---|---|---|
Wait time | Quantity | > | 90 | |
Lab result | Quantity | <= | 7.5 | |
Birth date | Date | >= | 1990/01/01 | n/a |
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