Section 2: Foundational Standards
Section 3: Clinical and Administrative Domains
Section 6: Rules and References

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HL7 Decision Support Service (DSS)


A Decision Support Service takes in patient data as the input and provides back patient-specific assessments and recommendations.  A Decision Support Service facilitates the implementation of clinical decision support capabilities in a scalable manner.  The service payloads used by a Decision Support Service (e.g., Consolidated CDA or Virtual Medical Record representations of patient data) are defined through other projects within HL7.

This specification is an update to the Decision Support Service Release 1 standard.  Compared to Release 1 of the standard, the main update is the addition of a Representational State Transfer (REST) Web service interface to the existing SOAP Web service interface.


HL7 Decision Support Service (DSS) may also go by the following names or acronyms:

"HL7 Decision Support Service, R2", "HL7 Decision Support Service, R1", DSS, DSS R2


  • Clinical and Public Health Laboratories
  • Immunization Registries
  • Quality Reporting Agencies
  • Regulatory Agency
  • Standards Development Organizations (SDOs)
  • Payors
  • Pharmaceutical Vendors
  • Healthcare Institutions (hospitals, long term care, home care, mental health) utilizing decision support systems
  • Clinical decision support system vendors
  • Clinical decision support knowledge providers (e.g., medical content vendors)
  • Clinical decision support knowledge consumers (e.g., EHR, PHR, Lab, HIS system vendors)
  • Emergency Services Providers
  • Local and State Departments of Health
  • Medical Imaging Service Providers


  • Enables various Decision Support Services to be leveraged using a standard interface
  • Supports scalable, interoperable clinical decision support
  • Facilitates cost-effective implementation of clinical decision support capabilities
  • Promotes interoperability
  • Helps clearly define expectations of how decision support services should interface with health information systems
  • Enables an interoperable marketplace of clinical decision support knowledge resources that can be accessed through a standard software interface


See the Implementation Guide for this Standard.


The Decision Support Service (DSS) effort was initiated in 2005 as a part of the HL7-OMG Healthcare Services Specification Project ( Adopted as an HL7 DSTU in 2006, as an OMG draft standard in 2009, and as an OMG normative standard in 2010, it became an HL7 normative standard in 2011.

The DSS standard defines the collective set of behaviors that one would expect a clinical decision support engine to perform. This functionality is required of most healthcare organizations and allows for the data collected in electronic health records and other clinical information systems to provide enhanced value for patients, clinicians, healthcare providers and payers. The challenge is that the lack of a standard makes the use of decision support services more costly and difficult.

The DSS standard is among the first healthcare standards specifically designed to support a service-oriented architecture (SOA), and it establishes a basis for collaboration with the Object Management Group (OMG). One key point to note is that the DSS standard provides a service interface specification, not the specification of a service implementation. This is a critical distinction in terms of SOA. There could be many different ways of implementing all or part of the functionality to support the behavior described in this specification.


Clinical Decision Support

Services Oriented Architecture


HL7 Decision Support Service (DSS)

(Download) (3.00 MB)


HL7 Version 3 Standard: Decision Support Service Release 2, DSTU Release 1 (View STU)

(Download) (1.66 MB)


HL7 Implementation Guide: Decision Support Service, Release 1
HL7 Implementation Guide: Decision Support Service, Release 1.1 (View STU)
(View Brief)


The standard is also available as part of the Health Level Seven Version 3 (V3) Normative Edition. See the HL7 Version 3 Product Suite for downloads.