Different Line Item Status Codes in Acknowledgment (ACK) Segment

The ACK segment in an X12 855 Purchase Order Acknowledgment is used to indicate the status of specific line items in the purchase order. 

It communicates whether the supplier accepts, rejects, or modifies the requested items in the original purchase order (850).

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Structure of the ACK Segment

• Purpose: Provides acknowledgment status codes, quantities, and other relevant details for a line item.
• Position: The ACK segment is typically found within the detail loop in the 855 transaction.

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ACK Segment Example

ACK*IA*100*EA***068*20231231~

Explanation:

1. ACK01 (Element 668) - Line Item Status Code
   Indicates the status of the line item.
2. ACK02 (Element 380) - Quantity
   The quantity acknowledged by the supplier.
3. ACK03 (Element 355) - Unit of Measurement
   Unit of measurement for the quantity (e.g., EA = Each, CA = Case).
4. ACK04 to ACK05 (Optional) - Price or Date References
   Provides additional data, such as unit price or expected shipping/delivery date.
5. ACK06 (Element 374) - Reference Number Qualifier
   Qualifier indicating what type of reference is provided.
6. ACK07 (Element 373) - Date
   Date relevant to the acknowledgment (e.g., delivery date).

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ACK01 (Line Item Status Code) Values

Below are the most common ACK01 codes and their meanings:

Code	Description
IA	Item Accepted
IB	Item Backordered
IC	Item Accepted - Changes Made
ID	Item Deleted
IE	Item Accepted - Price Changed
IF	Item Accepted - Quantity Changed
IH	Item on Hold
IP	Item Accepted - Pending
IR	Item Rejected
IS	Item Accepted - Substitution Made
IQ	Item Accepted - Quantity and Price Changed

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Key Notes

1. Multiplicity: Each ACK segment corresponds to a single line item in the purchase order.
2. Usage: The buyer uses the ACK segment data to understand the supplier's response to the order, such as:
• Whether the requested items are fully available.
• Changes to price, quantity, or delivery dates.
• Items that are backordered, substituted, or rejected.
3. Flexibility: Additional fields in the ACK segment can specify dates, reasons for changes, or other context.