Orders and Observations Work Group | Maturity Level : N/A | Standards Status : Informative | Compartments : Device , Encounter , Patient , Practitioner , RelatedPerson |
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OPERATION:
Observation
Statistics
stats
The official URL for this operation definition is:
http://hl7.org/fhir/OperationDefinition/Observation-stats
The Statistics operation performs a set of statistical calculations on a set of clinical measurements such as a blood pressure as stored on the server. This operation evaluates Observation resources having valueQuantity elements that have UCUM unit codes. Observations with a status of 'entered-in-error' will be excluded from the calculations.
The set of Observations is defined by 4 parameters:
subject
)
code
and
system
,
or
coding
)
or
period`)
statistic
)
Possible statistical analyses (see StatisticsCode ):
If
successful,
the
operation
returns
an
Observation
resource
for
each
code
with
the
results
of
the
statistical
calculations
as
component
value
pairs
where
the
component
code
=
the
statistical
code.
The
Observation
also
contains
the
input
parameters
patient
,
code
and
duration
parameters.
If
unsuccessful,
an
OperationOutcome
with
an
error
message
will
be
returned.
The client can request that all the observations on which the statistics are based be returned as well, using the include parameter. If an include parameter is specified, a limit may also be specified; the sources observations are subsetted at the server's discretion if count > limit. This functionality is included with the intent of supporting graphical presentation
URL: [base]/Observation/$stats
Parameters
Use | Name | Cardinality | Type | Binding | Documentation |
IN | subject | 1..1 | uri |
The subject of the relevant Observations, which has the value of the Observation.subject.reference. E.g. 'Patient/123'. Reference can be to an absolute URL, but servers only perform stats on their own observations | |
IN | code | 0..* | string |
The
test
code(s)
upon
which
the
statistics
are
being
performed.
Provide
along
with
a
system,
or
as
a
coding.
For
example,
the
LOINC
code
=
2339-0
(Glucose
[Mass/volume]
in
Blood)
will
evaluate
all
relevant
Observations
with
this
code
in
| |
IN | system | 0..1 | uri |
The system for the code(s). Or provide a coding instead | |
IN | coding | 0..* | Coding |
The test code upon which the statistics are being performed, as a Coding | |
IN | duration | 0..1 | decimal |
The time period of interest given as hours. For example, the duration = "1" represents the last hour - the time period from on hour ago to now | |
IN | period | 0..1 | Period |
The time period over which the calculations to be performed, if a duration is not provided | |
IN | statistic | 1..* | code | http://hl7.org/fhir/ValueSet/observation-statistics|4.5.0 (Required) |
average|max|min|count The statistical operations to be performed on the relevant operations. Multiple statistics operations can be specified. These codes are defined here |
IN | include | 0..1 | boolean |
Whether to return the observations on which the statistics are based | |
IN | limit | 0..1 | positiveInt |
If an include parameter is specified, a limit may also be specified to limit the number of source Observations returned. If the include paramter is absent or equal to "false" the limit parameter SHALL be ignored by the server | |
OUT | statistics | 1..* | Observation |
A
set
of
observations,
one
observation
for
each
code,
each
containing
one
component
for
each
statistic.
The
Observation.component.code
contains
the
statistic,
and
is
relative
to
the
Observation.code
and
cannot
be
interpreted
independently.
The
Observation
will
also
contain
a
subject,
effectivePeriod,
and
code
reflecting
the
input
parameters.
The
status
is
fixed
to
| |
OUT | source | 0..* | Observation |
Source observations on which the statistics are based |
If modifier extensions are present in the Observation, they must be accounted for by implementers. A modifier extension may affect the observation.value in a way that it should be excluded from the from the calculations.
This operation cannot be performed on observations that the user is not authorized to see. It is assumed that the server has identified and secured the context appropriately, and can either associate the authorization context with a single patient, or determine whether the context has the rights to the nominated patient, if there is one. If there is no nominated patient (e.g. the operation is invoked at the system level) and the context is not associated with a single patient record, then the server should return an error. Specifying the relationship between the context, a user and patient records is outside the scope of this specification.
Usage note: every effort has been made to ensure that the examples are correct and useful, but they are not a normative part of the specification.