Units of Measurement

quantities and units UCUM Units in RTM IHTSDO - Observable and Investigation Model Project ISO/IEC / telebiometrics (IDMP, ISO 11240)

from draft ISO/CD 11240

UCUM The 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 = L/L same unit and dimension! -> fully specified property required! 1 L

RTM -> Paul Schluter

harmonized RTM table

Units and Quantities meter centimeter inch cubic meter liter length volume body height volume of milk v = l 3 UNITDIMENSIONQUANTITY head diam. cardiac output per heart beat

IHTSDO Observable 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

IHTSDO Observable 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

IHTSDO Observable 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

IHTSDO Observable 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 continuants INHERES 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 sites HAS LOCATION substances HAS INGREDIENT RELATIVE TO substances

IHTSDO Observable 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).

IHTSDO Observable 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)

IHTSDO Observable and Investigation Model Project Working on Rules for translating LOINC names and cNPU codes into the SNOMED observables model. Viable approach for parts of nomenclature? Relation to RTM?

ISO/IEC Quantities and units Successor of ISO 31, IEC definitions, names, letter symbols and their use, relations, and signs and symbols used with them ISO TC 12 - Quantities and Units / IEC TC 25ISO TC 12 - Quantities and Units "style guide" for scientific publications

ISO/IEC ISO TC 12 - Quantities and Units ISO 80003: Physiological quantities and their units –ISO PHYSICS –ISO CHEMISTRY –IEC BIOLOGY –IEC CULTUROLOGY –IEC PSYCHOLOGY