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Friday, October 17, 2014

Take as Written

One of the requirements for the HITSP C32 as specified by AHIP was that a medication entry provide the free text sig.  That specification met the requirement by indicating that it could be found in the <text> element of the <substanceAdministration> element.  This has resulted in implementation confusion because some feel that it meant that ONLY the sig should appear in substanceAdministration/text, and others felt that it could be part of it, but that it could also include the medication and other details (such as preconditions or other cautions or instructions like take with food).

The latter interpretation is what the HL7 RIM specifies should appear in the medication template's substanceAdministration/text element.  Some systems want access to just the sig, and cannot determine where it begins or ends in the medication template.  So Structured Documents is now working on a new template that can be used within the Medication template to show JUST the sig. Rick Geimer and I have been tasked with coming up with a proposal.

Here's essentially the proposal that we discussed on the SDWG call yesterday.  We add a new template called "Medication Free Text Sig" (or some similar name) which provides the free text sig component of the medication.  This template becomes a recommended component of the substanceAdministration template now, and perhaps becomes required in future editions of C-CDA.  It looks something like this:

    <paragraph ID='med-1'>
      <content ID='medname-1'>Amlodipine-Benzapril 2.5-10mg</content>

      <content ID='sig-1'>one capsule daily</content>
    <substanceAdministration classCode='SBADM' moodCode='INT'>
      <text><reference value='#med-1'/></text>
      <consumable typeCode="CSM">
        <manufacturedProduct classCode="MANU">
            <code code="898352" 
      displayName="Amlodipine 2.5 MG/Benazepril hydrochloride 10 MG Oral Capsule"
              codeSystem="2.16.840.1.113883.6.88" codeSystemName="RxNorm">
              <originalText><reference value="#medname-1"/></originalText>
            <name>Amlodipine 2.5 MG / Benazepril hydrochloride 10 MG Oral Capsule</name>
      <entryRelationship typeCode='COMP'>
        <substanceAdministration classCode='SBADM' moodCode='INT'>
          <code code='422096002' displayName='Take' 
              codeSystem='2.16.840.1.113883.6.96' codeSystemName='SNOMED-CT'/>
          <text><reference value='#sig-1'/></text>

This component simply provides access to the free text content of the sig portion of the medication entry.  Like the travel history section, certified EHR systems could start using a template like this today.  Consider this my prescription for how to solve the problem.

   -- Keith