Vocabulary Issues

HL7 Concept Codes Mnemonic vs Numeric <administrative_gender_cd C="M" D="Male" S="&HL7.USA.Gender" R="3.0"/> <administrative_gender_cd C=10173" D="Male" S="&HL7.USA" R="3.0"/>

Mnemonic Codes NOT a mandate to use mnemonics With relatively small code sets (~2-50 codes), it would be permissible to use an alpha-numeric concept codes that may provide hints about the referenced concept -

Mnemonic Codes (Continued) Once assigned, codes could not be changed: CodeDesignation MGMedium Granularity IGIntermediate Granularity

Numeric Codes Unique, meaningless identifier assigned from HL7 V3 namespace

Mnemonic Codes Advantages –Compatible w/ HL7 V2 –More intuitive and directly human readable –If folks intend to use them anyway, we might as well deal with them for what they are Disadvantages –Issues resulting from confusion w/ designations –English-centric –Potentially misleading if incorrectly interpreted –Smaller namespace M vs 10173

Numeric Codes Advantages –Reduces possibility of misinterpretation –Reduces (but doesnt eliminate) language / case / character set / multi code issues –Reduces potential for confusion (M – Male, Married, …) Disadvantages –Requires outside resources to interpret –Requires central number assignment –Not directly compatible with existing HL7 V2 codes

We could have it both ways Code System MMale FFemale UNUnknown Code System Male 10174Female 10175Unknown Map M : F :

Questions 1)Should we allow the assignment of alpha-numeric concept codes in the HL7 V3 Code Systems? 2)If the answer to 1 is yes, should we support both schemes with a mapping or abandon the unique (within the HL7 V3 namespace) numbers completely?

Vocabulary Issues Issue 2: Multiple Codes per Concept

Multiple Codes per Concept <route_cd C=PO D=Swallow, Oral" S="RouteOfAdministration" R="3.0"/> <route_cd C=ORAL D=Swallow, Oral" S="RouteOfAdministration" R="3.0"/>

Multiple Codes per Concept Depending on earlier decision, may or may not be an issue for HL7 internal codes Still have to address external code sets Question: Do we need to support multiple codes per concept?

Vocabulary Issues Issue 3: Case Sensitive Codes

Case Sensitive Codes <unit_code C=m D=milli" S=UnitsOfMeasure" R="3.0"/> <route_cd C=M D=Meter" S=UnitsOfMeasure" R="3.0"/>

Case Sensitive Codes Issues 1)Many SQL databases (including Access) default to case insensitive 2)Possibility for confusion 3)Cannot control external code content

Case Sensitive Codes Proposed policy a)No two concept codes within the same code system may have the same value if case is ignored uL(microLiter)UL (Underline) b)Codes must match the case in the code system <units c=UL ….

Vocabulary Issues Issue 4: Code Character Set

Code Character Set Question: Do we support concept codes drawn from non character sets?

Vocabulary Issues Issue 5: ISO Code Sets

ISO Code Sets HL7 supports 3 categories of code system: –Internal –External –Imported Question: How do we deal with language codes, country codes, etc?

ISO Code Sets Policy as it stands today –ISO: You can publish for free but vendors must purchase a license (~$ per ???) –ANSI: You have to pay us $1000 just to publish the codes ISO codes are widely used (but not widely paid for)

ISO Code Sets Do we: A)Purchase the code sets and request that the vendors / institutions purchase licenses? B)Try to negotiate a package deal? C)Build our own? If so, how should translation be handled? D)Eliminate imported category for priced systems? E)Continue to research options? (How does W3C do it? How about IETF? UN? Post Office?...)