Units of Measurement
quantities and units
• UCUM• Units in RTM• IHTSDO - Observable and Investigation Model Project
• ISO/IEC 80000 / 80003 - telebiometrics• (IDMP, ISO 11240)
from draftISO/CD 11240
UCUMThe Unified Code for Units of Measure
• Codes for base units and derived units• Covers most units in practical use• freely available• published as XML file• lightweight maintenance process • unitsofmeasure.org
UCUM
• added units for RTM:– Wood units for vascular resistance:
[wood'U] := mm[Hg].min/L– B[10.nV] ( for using dB[10.nV] )
• future development:– add syntax rules for logarithmic units– rules for arbitrary units– road to ISO?
Lab: Reference ranges for blood tests
Unit alone is not enough!
• relative volume:1 L / 2 L = 0.5 L/L
• volume fraction:1 L / 3 L = 0.333 L/L
• same unit and dimension!
-> fully specified property required!
1 L
1 L
1 L
harmonized RTM table
IHTSDOObservable and Investigation Model Project
Example: • substance rate of renal excretion of
pregnanediol in micromoles per day (observable entity)– PROPERTY TYPE substance rate– CHARACTERIZES renal excretion of pregnanediol– PROCESS OUTPUT pregnanediol– UNITS micromoles per day– DIRECT SITE urine specimen
IHTSDOObservable and Investigation Model Project
Example: • mass concentration ratio of silver to creatinine in 24
hour urine (observable entity)– PROPERTY TYPE mass concentration ratio– CHARACTERIZES renal excretion of silver– PROCESS AGENT renal parenchyma– PROCESS DURATION 24 hours– PROCESS OUTPUT silver– RELATIVE TO creatinine– DIRECT SITE 24 hour urine specimen
IHTSDOObservable and Investigation Model Project
• PROPERTY TYPE • INHERES IN
– INHERENT LOCATION – INHERENT INGREDIENT
• CHARACTERIZES – PROCESS AGENT – PROCESS DURATION– PROCESS OUTPUT
• TOWARDS• RELATIVE TO, REL-TO PART-OF
IHTSDOObservable and Investigation Model Project
• PRECONDITION• SCALE• UNITS• TECHNIQUE• DIRECT SITE
observable
PROPERTY TYPE Property types
PROCESS DURATION
SCALE
Time frame
Scale types
DRAFT model for observables with a target that is a ‘quality’
independent continuantsINHERES IN
TOWARDS Functions, substances
UNITS units
TECHNIQUE techniques
OBS-TARGET
PRECONDITION Body states (challenges, fasting etc.), timings, sequence numbers, etc
DIRECT SITE Body structures, specimens
quality
sitesHAS LOCATION
substancesHAS INGREDIENT
RELATIVE TO substances
IHTSDOObservable and Investigation Model Project
• Property Type– This attribute is used to specify the type of
inherent quality or process that is to be observed.– Its values are abstract types of quality (length,
odor, concentration) or abstract types of process features (rate, speed), and do not include qualities that are located (length of arm, odor of urine), or given a value (elevated concentration).
IHTSDOObservable and Investigation Model Project
• Note: In a coming release of SNOMED CT, Measurement property will become a subtype of a new general concept Property type (qualifier value)
IHTSDOObservable and Investigation Model Project
• Working on Rules for translating LOINC names and cNPU codes into the SNOMED observables model.
• Viable approach for parts of 11073 nomenclature?
• Relation to RTM?
ISO/IEC 80000
• Quantities and units • Successor of ISO 31, IEC 60072• definitions, names, letter symbols and their
use, relations, and signs and symbols used with them
• ISO TC 12 - Quantities and Units / IEC TC 25• "style guide" for scientific publications
ISO/IEC 80003
• ISO TC 12 - Quantities and Units
• ISO 80003: Physiological quantities and their units– ISO 80003-2 PHYSICS– ISO 80003-3 CHEMISTRY– IEC 80003-4 BIOLOGY– IEC 80003-5 CULTUROLOGY– IEC 80003-6 PSYCHOLOGY