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4.1.1.1 As an aide-memoire for the clinician

Clinically relevant information in a patient record acts as an aide-memoire for the clinician, enabling him or her to recall previous interactions with the patient. Free-text notes can serve this purpose so it presents no special requirements for SNOMEDCT.

4.1.1.2 Structuring data entry

Structured data entry enhances the value of an electronic patient record in various ways. It may:

  • Simplify recording of frequently collected data;
  • Ensure that information is collected in a reliable and reproducible form;
  • Help clinicians to think logically about a patient's condition.

Clinical applications may combine several data entry methods applicable to different circumstances. Some of the most commonly used methods outlined below with notes on SNOMED CT requirements that arise directly from them:

  • Searching a coded terminology for matching terms using words or phrases;

See Text searches

  • Navigating a hierarchical structure to refine or generalize the meaning;

See Navigating relationships

  • Using templates or protocols to record structured information based on answers to questions or values entered on a particular data entry form;

See Subsets for specified contexts

  • Parsing of natural language to identify and retrospectively code and structure the data.
  • This may include typing, speech recognition and document scanning;

See Parsing or encoding free text

Data entry may require selection from a list of choices. Such lists must be manageable in size and appropriate to the needs of the user.

  • A multilingual, multidisciplinary terminology requires mechanisms that limit and/or prioritize access to terms and codes in ways that are appropriate to:

    • Languages and dialects.
    • Countries, organizations, disciplines, specialties and users.
    • Contexts within a record or protocol;

See Subsets

  • When a code's Description is to be displayed in a list that has not been derived from a text search, the term displayed must be intelligible and appropriate to the user;

See Terminology structure: preferred terms

When a code is entered in a record it may require structured entry of additional qualifying information.

  • Qualifying information may be coded.
    • For example, the code named "removal of kidney" may require a statement of laterality.

See Qualifying characteristics

  • Qualifying information may be numeric.
    • For example, the code named "hemoglobin measurement" may enable entry of a numeric value expressed in a substance concentration.

To meet all the needs for coded structured data entry in a patient record, a terminology must cover an adequate scope.

  • The main body of SNOMED CT should cover the required scope.

See Content scope

  • It is difficult to achieve this desirable outcome because individual organizations, specialties and users may need to use specific terms or coded meanings to meet their own operational requirements. Therefore, the structure of SNOMED CT should be designed to safely accommodate additions to meet different needs.

See Extensions

A clinical terminology requires frequent changes including new codes, new terms, and new or revised Relationships between the codes. The requirements for these changes include:

  • New threats to health.
  • Changes in understanding of health and disease process.
  • Introduction of new drugs, investigations, therapies and procedures.

See Content updates

4.1.1.3 Presentation

Presenting the content of a patient record in ways that highlight key information and indicate links between associated items may help a clinician to understand the patient's condition.

Presentation of information may be determined entirely by record structure without regard to the terminological resource (e.g. to present clinical information in date order, by author or by the type of recorded event).

  • It may be useful to select information for presentation based on its semantic content (e.g. listing procedures, investigation results or observations relevant to a particular disease process).

See Retrieval for presentation

4.1.1.4 Supporting decisions

Interfaces between recorded clinical information and appropriate decision support tools and reference works may assist the clinician to make the correct decisions of diagnosis, investigation and treatment.

  • Decision support requires selective retrieval and processing of information in an individual patient record to determine whether the patient has particular characteristics relevant to the decision support protocol. The algorithms for establishing the presence of characteristics need to take account of Relationships between coded meanings and other aspects of record structure. Performance is also important as decision support algorithms are typically run in real-time during data recording.

See Retrieval for decision support

  • Decision support algorithms may depend on numeric or other values associated with particular observations and the units in which such values are expressed.

See Kind-of-Value

  • Decision support algorithms need to take account of the context in which information is recorded. For example, the date of recording and any stated Relationships between individual items of information.

See Data structures and patient record architectures

  • Information of interest to decision support algorithms may include factors such as age, sex, clinical conditions, findings, operative procedures, medication and social/environmental factors such as occupation.

See Content scope

  • Authoritative reference works and/or available decision support tools may represent clinical meanings using codes or identifiers from other terminologies, classification or proprietary schemes. Mapping tables are required to allow applications that use a terminology to interface with these resources.

See Mapping to reference works

4.1.1.5 Communication

Effective delivery of high quality healthcare to an individual requires communication between those involved in providing care to that patient. This requirement includes communication within a team or organization and communication across organizational boundaries.

The primary objective of many clinical communications is to convey information to a human recipient. Professional and legal advice in several countries indicates that communications with this purpose should include human-readable text. It is considered to be unwise to rely on reconstituting text from coded representations. Coded data is therefore not relevant to the requirement for human-to-human communication.

Clinical communications may convey information for processing by a receiving application. This information may need to be retrieved and processed to meet requirements identified elsewhere in this document. To meet this requirement specification of messages (or other means of electronic communication) must permit the communication of SNOMED CT identifiers and associated structures.

See Data structures for communication

Communication specifications, such as those produced by HL7 and CENTC251, define structures designed to meet particular requirements. These used coded information in two distinct situations:

Coded elements that must be filled with codes enumerated in the specification.

These codes enumerated in the specifications are generally concerned with mission critical features of the message.

Some of the enumerated codes may have meanings that overlap with meanings of codes in a clinical terminology.

See Mapping to communication specifications

Coded element designed to be populated with clinical codes from any appropriate identifiable coding scheme.

The open coded elements are those where the full expressiveness of a terminology may be required.

Some of the open coded elements may be restricted to codes that express particular types of meaning.

For example, HL7 requires that coding schemes used in its message meet certain criteria, one of which is the ability to express limited subsets of codes appropriate to particular elements.

See Subsets for specified contexts

There are two situations in which communication of coded information may be of value for human-to-human communication.

Where the storage capacity or communication bandwidth is restricted. In this case, receiving systems must contain (or have real-time access to) a table listing the text Descriptions associated with each code.

See Availability for limited applications

Where there is a need for translation between the languages of the sender and the recipient. In this case, a coded representation of a meaning may allow display of the appropriate Description in the recipient's language.

See Availability of terms in different languages

Recording a particular coded meaning may trigger a communication, and receipt of a particular coded meaning may trigger specific processing in the receiving system. For example recording a decision to prescribe a medicine might trigger an electronic prescription sent to the pharmacy. Receipt of such a prescription might trigger dispensing and stock management activities.

The Relationship of a trigger is an additional characteristic of a coded meaning that may be context dependent.

See Additional characteristics

4.1.1.6 Patient involvement

There is an increasing trend toward the involvement of patients in their own care. Patients may have a wish or indeed a right to view, and comprehend, their own records.

If SNOMED CT is to meet this requirement the inclusion of patient-friendly colloquial terms should be considered. However, this possible requirement should not take precedence over the need for an accurate professional terminology.

See Content scope

Patients may also be allowed to contribute to their own records. For example, diabetic patients may record their blood glucose or insulin regime. In this case the patient may need to be a user of SNOMED CT .

See Availability to patients


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