An ELEMENT to represent the result of an estimated body water composition measurement expressed in litres (L). There are a number of ways of calculating this value (e.g. body weight*0.6). Watson: Male TBW = 2.447 - (0.09156 x age) + (0.1074 x height) + (0.3362 x weight) Female TBW = -2.097 + (0.1069 x height) + (0.2466 x weight) Hume-Weyers: Male TBW = (0.194786 x height) + (0.296785 x weight) - 14.012934 Female TBW = (0.34454 x height) + (0.183809 x weight) - 35.270121 Note: the observations used to derive estimated body water composition have been modelled explicitly with the exception of age. It should be noted however that although age has not been modelled explicitly that it is required in some methods (e.g. Watson) of estimating body water composition.

Attributes

Name	Data type	Occurs	Description	Value Constraints
name	SC	1..1	The name, expressed as a coded value or as plain text, specifies the clinical or administrative concept to which this EHR node corresponds, as labelled in the EHR system in which it was first committed.	value Literal value(s): PROPERTY_OBSERVATION_ELEMENT
rc_id	II	1..1	The globally-unique identifier by which this node in the EHR hierarchy is referenced in the EHR system to which the data were first committed. This identifier shall be retained by the EHR Recipient and re-used whenever this RECORD_COMPONENT is subsequently included in another EHR_EXTRACT.
meaning	CD.CV.SCT	1..1	A coded representation of the result of an estimated body water composition measurement.	code Semantic expression constraint
synthesised	BL	1..1	This attribute value shall be TRUE if this RECORD_COMPONENT has been created in order to comply with this standard , but this point in the EHR hierarchy has no corresponding node in the EHR from which it was extracted.	value Default value: true
obs_time	IVL_TS	0..1	The date and time, or interval, of the estimated body water composition observation.
value	PQ	1..1	The value of the result of an estimated body water composition measurement expressed in litres (L).	unit Literal value(s): L

COMPONENT RELATIONSHIPS

Subject of relationships

Name	Object of relationship	Occurs	Dependency
HasAnnotation	Text	0..*	INDEPENDENT
IsDerivedObservation	BodyWeightObservation	0..*	INDEPENDENT
IsDerivedObservation	BodyHeightObservation	0..*	INDEPENDENT

Object of relationships

Name	Subject of relationship	Occurs	Dependency
IsDerivedObservation	Kt/VObservation	0..*	INDEPENDENT

Item of ENTRY Domain Models

Kt/V

Reference Model Type

PROPERTY_OBSERVATION_ELEMENT