When the first message definition was created, an OBX segment definition was created. In this segment definition, field 5 is defined to be of type ST (text string):

This segment will successfully match messages whose OBX segments have text in field 5, but will not match OBX segments that have a numeric value in field 5. To indicate this, define a segment identity for the existing OBX segment to state that this segment expects text in field 5:

• In the Workspace panel at left, double-click the OBX segment definition.
• In the Segment - OBX window, click Identity. A Segment Identity table appears:
• In the Field column, click ... (ellipsis).
• In the Pick Identity Field window, select 2 - Value Type. Click OK.
• In the Value column, type ST. The Workspace panel now indicates that the OBX segment has ST as its segment identity:

The next step is to define a second copy of the OBX segment that has NM as its segment identity. This segment definition will represent incoming OBX segments whose OBX.5 value is numeric. To define this second OBX segment:

• From the Workspace menu, select Import Segments From Library.
• In the Import Segments From Library window, in the list box next to Import segments from a library, select HL7 2.6. Click Next.
• Select the OBX check box. Click Next and then Finish. A new OBX segment definition appears in the Workspace:

• In the Workspace, double-click the new OBX segment definition.
• In the Segment - OBX window, locate row 5, which is the row whose Name column is Observation Value.
• In Row 5, in the Data Type column, click ... (ellipsis). From the list box that appears, select NM.
• Click Identity. The Segment Identity table appears.
• In the Field column, click ... (ellipsis).
• In the Pick Identity Field window, select 2 - Value Type. Click OK.
• In the Value column, type NM. The Workspace panel now indicates that this new OBX segment has NM as its segment identity: