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History description 2014-03-26: Lock all vaue sets untouched since 2014-03-26 to trackingId 2014T1_2014_03_26
description:
Description: An act that is intended to result in new information about a subject. The main difference
between Observations and other Acts is that Observations have a value attribute. The
code attribute of Observation and the value attribute of Observation must be considered in combination to determine the semantics
of the observation.
Discussion:
Structurally, many observations are name-value-pairs, where the Observation.code (inherited
from Act) is the name and the Observation.value is the value of the property. Such
a construct is also known as a variable (a named feature that can assume a value)
hence, the Observation class is always used to hold generic name-value-pairs or variables,
even though the variable valuation may not be the result of an elaborate observation
method. It may be a simple answer to a question or it may be an assertion or setting
of a parameter.
As with all Act statements, Observation statements describe what was done, and in
the case of Observations, this includes a description of what was actually observed
(results or answers); and those results or answers are part of the observation and
not split off into other objects.
The method of action is asserted by the Observation classCode or its subclasses at
the least granular level, by the Observation.code attribute value at the medium level
of granularity, and by the attribute value of observation.methodCode when a finer
level of granularity is required. The method in whole or in part may also appear in
the attribute value of Observation.value when using coded data types to express the
value of the attribute. Relevant aspects of methodology may also be restated in value
when the results themselves imply or state a methodology.
An observation may consist of component observations each having their own Observation.code
and Observation.value. In this case, the composite observation may not have an Observation.value
for itself. For instance, a white blood cell count consists of the sub-observations
for the counts of the various granulocytes, lymphocytes and other normal or abnormal
blood cells (e.g., blasts). The overall white blood cell count Observation itself
may therefore not have a value by itself (even though it could have one, e.g., the
sum total of white blood cells). Thus, as long as an Act
is essentially an Act of recognizing and noting information about a subject, it is
an Observation, regardless of whether it has a simple value by itself or whether it
has sub-observations.
Even though observations are professional acts (see Act) and as such are intentional
actions, this does not require that every possible outcome of an observation be pondered
in advance of it being actually made. For instance, differential white blood cell
counts (WBC) rarely show blasts, but if they do, this is part of the WBC observation
even though blasts might not be predefined in the structure of a normal WBC.
Clinical documents commonly have Subjective and Objective findings, both of which
are kinds of Observations. In addition, clinical documents commonly contain Assessments,
which are also kinds of Observations. Thus, the establishment of a diagnosis is an
Observation.
Examples:
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Recording the results of a Family History Assessment
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Laboratory test and associated result
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Physical exam test and associated result
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Device temperature
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Soil lead level
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Value Set ActClassObservation 2014‑03‑26
Final
