title: Is OBR segment required to view the OBX segment attachments in HL7 message?
body: <p>I'm trying to parse an HL7 message file which is of version 2.3.1. OBX segment is coming as null when the message is parsed.</p>
  
  <p>If I don't have OBR segment in HL7 message, Terser is failing to fetch the OBX segment values (it's returning null values), so is OBR segment mandatory to view OBX attachments in an HL7 message?  </p>