What is a VMD File?

A VMD or Visual Message Definition File are used in IguanaX to define the structure, format and identity of HL7v2 and EDI X12 messages during processing. A VMD file contains:

Message Definitions: The message definition includes a breakdown of segments and their corresponding fields, as well as the order and cardinality (required or repeating) of those segments and fields.
Matching Rules: These rules help Iguana recognize and differentiate between different message definitions.

IguanaX contains importable VMD definitions for:

HL7v2 Libraries (v2.1 to 2.7)
EDI X12 HIPAA Libraries (v4010 and 5010)

VMD files are a big part of what makes IguanaX an easy environment to handle HL7 and X12 in. Let’s look at an example HL7 message and VMD:

HL7 is a delimiter based structure which is not very readable

See how this raw HL7 message is not very readable:

MSH|^~\&|MESA_ADT|XYZ_ADMITTING|iFW|ZYX_HOSPITAL|||ADT^A01|103102|P|2.4||||||||
EVN||200007010800||||200007010800
PID|||583295^^^ADT1||DOE^JANE||19610615|M-||2106-3|123 MAIN STREET^^GREENSBORO^NC^27401-1020|GL|(919)379-1212|(919)271-3434~(919)277-3114||S||PATID12345001^2^M10|123456789|9-87654^NC
NK1|1|BATES^RONALD^L|SPO|||||20011105

VMDs give a dictionary of each part of an HL7 or X12 message

The entries in the dictionary give the names and descriptions of the fields in the message.

Iguana is able to use this dictionary to make it more intuitive as to what the fields mean.

VMD files are formatted in simple JSON

VMDs in IguanaX have a simple JSON format. To view a VMD as JSON in the Translator, click on the .vmd file edit icon ⋮ , and click Show Source.

"ADTA01":{
  "desc":"Admit/visit notification",
  "type":"message",
  "children":[
   {"type":"MSH",       "desc":"Message Header"                         ,"req":true},
   {"type":"SFT",       "desc":"Software Segment"                       ,"repeats":true},
   {"type":"UAC",       "desc":"User Authentication Credential Segment"},
   {"type":"EVN",       "desc":"Event Type"                             ,"req":true},
   {"type":"PID",       "desc":"Patient Identification"                 ,"req":true},
   {"type":"PD1",       "desc":"Patient Additional Demographic"        },
   {"type":"ARV",       "desc":"Access Restriction"                     ,"repeats":true},
   {"type":"ROL",       "desc":"Role"                                   ,"repeats":true},
   {"type":"NK1",       "desc":"Next of Kin / Associated Parties"       ,"repeats":true},
   {"type":"PV1",       "desc":"Patient Visit"                          ,"req":true},
   {"type":"PV2",       "desc":"Patient Visit - Additional Information"},
   {"type":"ARV",       "desc":"Access Restriction"                     ,"repeats":true},
   {"type":"ROL",       "desc":"Role"                                   ,"repeats":true},
   {"type":"DB1",       "desc":"Disability"                             ,"repeats":true},
   {"type":"OBX",       "desc":"Observation/Result"                     ,"repeats":true},
   {"type":"AL1",       "desc":"Patient Allergy Information"            ,"repeats":true},
   {"type":"DG1",       "desc":"Diagnosis"                              ,"repeats":true},
   {"type":"DRG",       "desc":"Diagnosis Related Group"               },
   {"type":"PROCEDURE", "desc":""                                       ,"repeats":true},
   {"type":"GT1",       "desc":"Guarantor"                              ,"repeats":true},
   {"type":"INSURANCE", "desc":""                                       ,"repeats":true},
   {"type":"ACC",       "desc":"Accident"                              },
   {"type":"UB1",       "desc":"UB82"                                  },
   {"type":"UB2",       "desc":"Uniform Billing Data"                  },
   {"type":"PDA",       "desc":"Patient Death and Autopsy"             }]},

This video explains the benefit:

whyvmd.mp4