---
title: File837AckBuilder
summary: API reference for File837AckBuilder.
status: draft
owner: SAIF Doc Gen
last_reviewed: 2026-09-24
library: SAIF.Domain
reference_type: package
---

# File837AckBuilder

`File837AckBuilder` renders a 999-style functional acknowledgement EDI file for a processed 837 batch (part of operation OP-DOM-12's EOB/acknowledgement output chain, alongside `File835Builder`): given the inbound `IEdiFile` and the batch, it writes the ISA/GS header segments, walks each functional group and transaction set to build AK2/AK9-style response segments, and writes the trailer segments, producing the outbound acknowledgement `IEdiFile`. Its per-segment layout was not traced statement-by-statement in the source analysis, so several individual segment-writing methods are documented from their signatures and surrounding calls*.

## Purpose
- Builds the complete outbound acknowledgement file for an inbound 837 batch: header segments, one response block per functional group/transaction set, and trailer segments.
- Provides a batch-date/duplicate-submission guard (`CheckBatchWithFileSegmentNotProcessed`, `GetFileBatchDate`) so acknowledgement generation can detect whether a file's batch date has already been processed.

## Context
- Namespace: `SAIF.Domain.Claims.Ebilling`
- Assembly/package: `SAIF.Domain` (`Domain/SAIF.Domain/SAIF.Domain.csproj`, .NET Framework 4.6.2 class library)

## Public members
| Member | Signature | Purpose |
| --- | --- | --- |
| Build837AckFile | `public static IEdiFile Build837AckFile(IEbillingQueryProvider ebillingQueryProvider, IUserProfileService userProfileService, IEdiFile file, EbillBatch batch, bool isProductionRun)` | Builds the complete outbound acknowledgement `IEdiFile` for the batch: writes header segments, processes each functional group in the inbound file, then writes trailer segments. |
| ProcessFunctionalGroup | `public static void ProcessFunctionalGroup(EdiFile outfile, EbillBatch batch, IFunctionalGroup functionalGroup, ref int transactionSetControlCount, ref int transactionSetSegmentCount)` | Writes the functional-group header, per-transaction-set response segments, and functional-group trailer for one inbound functional group, updating the running control/segment counters by reference*. |
| WriteHeaderSegments | `public static void WriteHeaderSegments(EdiFile outfile, EbillClearinghouse clearinghouse, EbillBatch batch, bool isProductionRun)` | Writes the ISA and GS interchange/group header segments that open the acknowledgement file. |
| WriteFunctionalGroupHeaderSegments | `public static void WriteFunctionalGroupHeaderSegments(EdiFile outfile, EbillBatch batch, IFunctionalGroup functionalGroup, int transactionSetControlCount)` | Writes the ST/BHT-level header segments that open a functional group's response transaction set. |
| WriteTransactionGroupSegments | `public static void WriteTransactionGroupSegments(EdiFile outfile, ITransactionSet transactionGroup)` | Writes the response body segments for a single transaction set within a functional group*. |
| WriteFunctionalGroupTrailerSegments | `public static void WriteFunctionalGroupTrailerSegments(EdiFile outfile, IFunctionalGroup functionalGroup, int transactionSetControlCount, int stSegmentCount)` | Writes the SE/GE-level trailer segments that close a functional group's response transaction set. |
| WriteTrailerSegments | `public static void WriteTrailerSegments(EdiFile outfile, EbillBatch batch, int transactionSetControlCount)` | Writes the IEA interchange trailer segment that closes the acknowledgement file. |
| CheckBatchWithFileSegmentNotProcessed | `public static bool CheckBatchWithFileSegmentNotProcessed(DateTime fileBatchDate, IEbillingQueryProvider queryProvider, EbillClearinghouse clearinghouse)` | Reports whether the given file batch date has not already been processed for the clearinghouse, guarding against re-acknowledging a duplicate submission*. |
| GetFileBatchDate | `public static DateTime GetFileBatchDate(I837File file)` | Extracts the batch date recorded in the parsed 837 file so it can be compared against previously processed batches. |

## Behavioral notes
- `ProcessFunctionalGroup` mutates its running counters through `ref` parameters rather than returning them, so callers must read the updated `transactionSetControlCount`/`transactionSetSegmentCount` values after the call rather than any return value*.
- The exact response segments written per transaction set were not traced line by line from the source; `WriteTransactionGroupSegments`'s purpose is inferred from its name, parameters, and position in the build pipeline**.

> **Note:** Statements marked with `*` were inferred from code structure, naming conventions, or
> contextual evidence where direct confirmation was not available in source artifacts. Statements
> marked with `**` could not be confirmed; treat as unknown until verified.

## Sources
- `Domain/SAIF.Domain/Claims/Ebilling/File837AckBuilder.cs`