[Category: Dates, Times, & Schedules]The "Combined Type" Time IntervalThe article
Combining time intervals in CDA, introduces and overviews the most sophisticated form of time expression in a
CDA document, which we term the "combined type" time interval.
In the
XML representation of the "combined type" time interval in CDA, multiple
effectiveTime or
useablePeriod elements are used alongside each other and are combined with the
operator attribute.
Only certain instances of the
effectiveTime element in CDA documents are of this special "combined type".
Refer also to the articles
The effectiveTime element,
The operator attribute, and
Using “Parenthetical Expressions” in SIGs for additional information about the "combined type" time interval.
The "Combined Type" Time Interval is Formally the SXCM_TS Data TypeIn the
XML Schema for CDA documents, the data type name assigned to elements that are of this special "combined type" time interval, is
SXCM_TS.
Only a Few effectiveTime Elements are of SXCM_TS Data TypeThe elements in a CDA document that are assigned the data type
SXCM_TS and are commonly used, are named
effectiveTime.
However, not all elements named
effectiveTime have this data type. In fact, most
effectiveTime elements have the data type
IVL_TS, which represents a regular contiguous time interval - refer to the article
Time intervals in CDA, for more information.
The
effectiveTime element located directly under
ClinicalDocument is of type
TS, which represents a time-stamp (a single moment in time) - refer to the article
Moments in time in CDA, for more information.
The
effectiveTime elements that have the data type
SXCM_TS ("combined type" time intervals), are those located directly under the
susbtanceAdministration clinical act statement element and are used to express the times for administering medications and other substances.
SXCM_TS Also Used for Flexibility with a Single effectiveTime ElementThe
effectiveTime element located under the
supply clinical act statement, is of type
SXCM_TS as well.
However, in this context the
SXCM_TS data type is not intended for use of the full expressive power of the the
SXCM_TS data type (with the the
operator attribute being used to combine multiple
effectiveTime elements).
Rather, the
SXCM_TS data type is used with
supply/effectiveTime due to another characteristic of this data type. The
SXCM_TS data type allows the
effectiveTime element to be either of data type
IVL_TS or of data type
TS, using the
xsi:type attribute to distinguish between them.
The CDA specification and XML Schema, declare
supply/effectiveTime to be of type
SXCM_TS, but at the same time limit the maximum number of occurrences of
supply/effectiveTime to one. Since only one
effectiveTime element can be used, it's not possible to combine multiple
supply/effectiveTime elements with the
operator attribute (the way it works in
substanceAdministration/effectiveTime).
Only the "flexibility benefits" (not the "combining of interval benefits") of the
SXCM_TS data type are relevant for
supply/effectiveTimeThe Data Type SXCM_TS is Also Used with the useablePeriod ElementIn addition to its use with
effectiveTime, the
SXCM_TS data type is also used with the
useablePeriod element that is a sub-element of
addr,
telecom, and
reference elements and is used to indicate that the phone number, address, etc. is only valid during certain times (e.g. a summer-home address, or a previous phone number that is no longer in use). Refer to the articles
The addr element and
The telecom element, for additional information.
With the
useablePeriod element, the full capabilities of the
SXCM_TS data type are used (multiple
useablePeriod elements with the
operator attribute to combine them, are supported).
Use of xsi:type Attribute with SXCM_TS Data TypeWhenever a
useablePeriod element or
effectiveTime element with data type
SXCM_TS is used, the
xsi:type attribute must be used with it. Refer to the article
What is the role of the xsi:type attribute in CDA?, for more information about
xsi:type and why it is needed for elements that can take on more than one XML Schema data type.
However, there is one important exception. If the useablePeriod element or effectiveTime element with data type SXCM_TS is used as a time-stamp (aka "moment in time") which has the data type TS, the xsi:type attribute should NOT be used. The reason for this is due to a technicality of how the XML Schema definition for
SXCM_TS works. An element of type
SXCM_TS is actually already of type
TS (its "base type") and thus schema validation will fail if
xsi:type="TS" is explicitly indicated.
For all other time data types (
IVL_TS,
PIVL_TS, and
EVIL_TS - refer to the article
Combining time intervals in CDA for a summary of these types and links to additional articles that describe each in detail) that are used in a
useablePeriod element or
effectiveTime element with data type
SXCM_TS,
xsi:type must be used.
Note that the guidance above for using
xsi:type in a
useablePeriod element or
effectiveTime element with data type
SXCM_TS apply regardless of whether a single
useablePeriod element or
effectiveTime element with data type
SXCM_TS is used - or whether a series of such elements is used and they are combined via the
operator attribute.
ExamplesFor examples of the use of elements with the
SXCM_TS data type to represent "combined type" time intervals, refer to the article
Combining time intervals in CDA.
Other CDA PRO Know Articles Referenced In This Article