Update to most recent version of LOI

Please update to point to the most recent version:

HL7 Version 2.5.1 Implementation Guide: Laboratory Orders from EHR (LOI) Release 1, STU Release 3 - US Realm Link to specification = Link to DSTU comment page = 

Value Set IG: Link to specification = For comments on the Value set Companion guide, please submit DST comments under the guide that the vocabulary belongs to - if for the document itself, just pick one of the guides and submit there with the reference to the companion guide document and page number/section or applicable spreadsheet

LOI ISA Update.docx