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:
-
Recording the results of a Family History Assessment
-
Laboratory test and associated result
-
Physical exam test and associated result
-
Device temperature
-
Soil lead level