---
title: DtpSegment
summary: API reference for DtpSegment.
status: draft
owner: SAIF Doc Gen
last_reviewed: 2026-09-15
library: SAIF.Framework.Common.Files
reference_type: package
---

# DtpSegment

`DtpSegment` models the X12 DTP date/time period segment, used throughout 837 claim transactions to attach a qualified date or date range to a claim/service line. When `Format` is left unset it defaults to `"D8"` for a single date or `"RD8"` for a range depending on whether `EndDate` is set ([BR-045](../../business-rules.md#br-045-dtp-format-defaults)), and the date value itself is interpreted differently depending on the format qualifier in force ([BR-046](../../business-rules.md#br-046-dtp-values-interpreted-by-format-qualifier)).

## Purpose
- Represents the DTP segment identity via `SegmentId` returning the literal `"DTP"` ([BR-020](../../business-rules.md#br-020-first-element-is-the-segment-identifier)).
- Carries `DateTimeQualifier`, `Format`, `StartDate`/`EndDate`, and their raw string equivalents `StartDateString`/`EndDateString`.
- Defaults `Format` to `"D8"` when `EndDate` is null or `"RD8"` when `EndDate` is set, if `Format` was left as an empty string before `Build()` is called ([BR-045](../../business-rules.md#br-045-dtp-format-defaults)).
- Interprets the date value according to the format qualifier on `Fill()`: `"RD8"` splits the value on `-` into start/end dates, `"D8"` reads a single date, `"DT"` reads a combined date+time value, and `"TM"` sets `StartDate` to `DateTime.MinValue` while retaining the raw time text in `StartDateString` ([BR-046](../../business-rules.md#br-046-dtp-values-interpreted-by-format-qualifier)).

## Context
- Namespace: `SAIF.Common.Files.Edi.Segments`
- Assembly/package: `SAIF.Framework.Common.Files`

## Public members
| Member | Signature | Purpose |
| --- | --- | --- |
| SegmentId | `string SegmentId { get; }` | Returns the literal X12 segment identifier `"DTP"`. |
| DateTimeQualifier | `string DateTimeQualifier { get; set; }` | The code qualifying what the date/period represents (DTP01), element 1. |
| Format | `string Format { get; set; }` | The date/time format qualifier (DTP02: `"D8"`, `"RD8"`, `"DT"`, or `"TM"`), element 2; defaulted on `Build()` when left empty ([BR-045](../../business-rules.md#br-045-dtp-format-defaults)). |
| StartDate | `DateTime StartDate { get; set; }` | The parsed start (or only) date of the period, derived from element 3 according to `Format` ([BR-046](../../business-rules.md#br-046-dtp-values-interpreted-by-format-qualifier)). |
| EndDate | `DateTime? EndDate { get; set; }` | The parsed end date of the period when `Format` is `"RD8"`; null for single-date formats. |
| StartDateString | `string StartDateString { get; set; }` | The raw start-date/time substring read from element 3 before date parsing. |
| EndDateString | `string EndDateString { get; set; }` | The raw end-date substring read from element 3 when `Format` is `"RD8"`. |
| Build | `IEdiSegment Build()` | Creates a `SegmentBuilder("DTP")`, adds `DateTimeQualifier`, defaults and adds `Format`, and adds element 3 as either `StartDate.ToString("hh24mm")`-equivalent time text (for `"TM"`) or `DateMaker.EdiFileDateString(StartDate, EndDate)`, returning the built segment. |
| Fill | `void Fill(IEdiSegment segment)` | Reads `DateTimeQualifier` and `Format`, then switches on `Format` to split/parse element 3 into `StartDate`/`EndDate`/`StartDateString`/`EndDateString` per format-specific rules ([BR-046](../../business-rules.md#br-046-dtp-values-interpreted-by-format-qualifier)). |
| Parse | `static DtpSegment Parse(IEdiSegment segment)` | Instantiates a new `DtpSegment`, calls `Fill(segment)` on it, and returns it. |

## Behavioral notes
- For `"TM"` format, `Fill()` sets `StartDate` to `DateTime.MinValue` and preserves only the raw time text in `StartDateString`, since a bare time value cannot be represented as a full `DateTime` without a date component*.
- An unrecognized `Format` value falls through the `switch` in `Fill()` with no branch executed, leaving `StartDate`/`EndDate`/`StartDateString`/`EndDateString` at their default values*.

> **Note:** Statements marked with `*` were inferred from code structure, naming
> conventions, or contextual evidence where direct confirmation was not available
> in source artifacts.

## Sources
- Common\SAIF.Common.Files\Edi\Segments\DtpSegment.cs