837 File Structure

The organizational layout of every 837 electronic file follows a standard format. The format strategically places each control segment in a specific order because each control segment specifies the type of data that can be transmitted within that control segment. The control segment headers always identify when new segments of information are going to begin, while the control segment trailers always identify when the data within a control segment is finished. The diagram below details the standard format and placement of each control segment in an 837 electronic file.

Some of the actual data submitted in these control segments may be different depending on the type of 837 file, the type of information that the control segments specify are the same for each 837 file (Professional, Institutional, and ADA).

The Interchange Envelope contains the control data for the entire electronic file.

The ISA segment always begins an 837 electronic file. There is only one ISA segment in an 837 and the only type of data that can be transmitted is EDI control data. The EDI control data is required and includes the following:

The IEA segment always ends an 837 electronic file. There is only one IEA segment in an 837 and the only type of data that can be transmitted is EDI control data. The EDI control data is required and includes the following:

The Functional Groups contain the control data for the transaction sets (ST/SE segments) that are imbedded in the Functional Group Control Segments (GS/GE). There can be multiple Functional Groups within the electronic file and they always fall between the ISA/IEA segments.

The GS segment always begins a Functional Group Control Segment. There can be multiple GS segments in an 837 file. However, a GS segment is always followed by its associated GE segment before another GS segment can start. The only types of data that can be transmitted in a GS segment are identifiers that define the type of transaction sets (ST/SE) that are included within the functional group. This data is required and includes the following:

The GE segment, which indicates the end of the functional group, always follows the final transaction set (ST/SE) that is imbedded in the functional group. The only type of data that can be transmitted in this segment includes:

The Transaction Sets contain the control data for the Loop Control Segments (LS/SE segments) that are imbedded in the Transaction Sets Control Segments (ST/SE). There can be multiple Transaction Sets within the electronic file and they will always fall between the GS/GE Functional Group Control Segments.

The ST segment always indicates the start of a transaction set. There can be multiple ST segments in an 837 file. However, each ST segment will always end with its associated SE segment before another ST segment can start. The ST segment and its data are required. The only type of data that can be transmitted in this segment includes:

In addition to these data elements, each ST segment in the 837 file must include two unique data segments: Beginning of Hierarchical Transaction (BHT) and Transmission Type Identification (REF).

The BHT segment is used to define the business hierarchical structure of the transaction set (ST/SE segment).

The REF segment is used to specify identifying information, which includes:

The SE segment, which indicates the end of the transaction set, always follows the final Loop Control Segment (LS/LE) that is imbedded in the transaction set. The only type of data that can be transmitted in this segment includes:

The Loop Control Segments contain the data that identify the specific claim information. The Loop data segments that are imbedded within a transaction set (ST/SE) have been standardized with a name and a number (for example, 1000A Submitter Information and 1000B Receiver Information).

In addition, within these loop data segments there are data elements that are used to specify the same type of information within different loops. These elements have specific naming conventions which signify the type of information they define (for example, the element NM1 always specifies Individual or Organizational Name and PER is always Administrative Communications Contact Information, regardless of the segments they are used in).

The first table below outlines the repeating elements and defines the type of information they specify, while the second table outlines each loop data segment and the elements that are associated with the loop.

The loop data segments that are outlined in this table are the loops that are required to be in the 837 electronic file. There are more loops than are listed here; however, they are not required and are dependent upon the nature of the claim/encounter. Non-required loop data segments are automatically included in the 837 by the application when necessary.