EDI 810 Invoice: Segments, Required Fields and How to Match One to a PO

Short answer

An EDI 810 is the X12 electronic invoice: the transaction set a supplier uses to bill a buyer for goods or services, usually after receiving that buyer’s purchase order. For the person in accounts payable at a lab or clinic, the useful skill is reading it against the order: the invoice number and PO number in the BIG segment, the PO line number and unit of measure in each IT1 line, and the invoice total in TDS. The standard leaves many choices to each trading partner, so the buyer’s own 810 guide decides what is required.

What an EDI 810 is and who sends it

X12, the standards body that maintains the 810, describes it as the transaction set that can be used for the customary and established business practice of billing for goods and services provided. X12 is chartered by the American National Standards Institute, each transaction set is maintained by a subcommittee of its Accredited Standards Committee, and the standard is published once a year in January.

The supplier sends the 810; the buyer receives it. In the usual flow it answers a purchase order, which is why the 810 is the natural next document after the EDI 850 purchase order. If the supplier also announces shipments electronically, the EDI 856 advance ship notice sits between the two. For the general idea of exchanging these documents between computer systems, see the dictionary entry on electronic data interchange (EDI) in medical supply procurement.

Segment walk-through

An 810 is a sequence of segments, each a short line of data elements. In the 003040 layout shown in the Stedi X12 reference, the mandatory pieces are the ST header, the BIG beginning segment, at least one IT1 line-item loop, the TDS total, the CTT transaction totals and the SE trailer. Most other segments, including currency (CUR), reference numbers (REF), contacts (PER), terms (ITD), dates (DTM), taxes (TXI) and service or allowance charges (SAC), are optional in the standard. A buyer’s guide may turn an optional segment into a required one.

• ST and SE open and close the transaction set. In one buyer guide (Cooper Standard), ST01 accepts only the code 810. SE carries the count of segments in the set, and that count includes the ST and SE segments themselves.
• BIG identifies the invoice. In the two buyer guides cited below, BIG01 is the invoice date, BIG02 the invoice number, BIG03 the purchase order date and BIG04 the purchase order number. BIG07 marks the transaction type; one guide uses CR for a credit memo and DI for a debit invoice.
• IT1 carries the basic and most frequently used line-item data: the lines being invoiced, with quantity, unit of measure and unit price.
• TDS carries the total invoice amount and discounts.
• CTT carries the line-item count (CTT01 is the number of IT1 segments) and, if the supplier uses it, a hash total of the quantities invoiced in IT102.

One buyer guide shows this sample BIG segment: BIG*20060424*9929293*20060420*5000002341***DI. Read left to right: invoice date 24 April 2006, invoice number 9929293, PO date 20 April 2006, PO number 5000002341, and DI as a debit invoice.

Reading BIG and IT1 against the purchase order

The point of matching is that the invoice should trace back to an order you actually placed. Two fields do most of the work.

• BIG04 to the PO number. This is the key to finding the original order. In one buyer guide it is marked must-use; in another it is merely used, so a supplier setting up with two buyers may be asked for it differently.
• IT101 to the PO line number. One buyer guide states that the IT101 value is the line item number from the original purchase order, must match it, and should appear only once on the invoice.
• IT103 to the ordering unit. Another buyer guide requires the unit of measure to match the unit of measurement code in the earlier document it references.

TDS totals and implied decimals

TDS amounts are sent without a decimal point. One buyer guide gives the example that an invoice total of $305.02 is sent as 30502, and requires the total to be rounded to the nearest cent. Check which decimal rule your own partner guide uses before comparing a TDS total with the sum of the lines.

Tax handling is a partner decision, not a standard one. One buyer guide says that for its US vendors taxes should not be included in the TDS total, while for its Canada and Asia-Pacific vendors taxes should be included. The same guide shows the CUR segment carrying the currency, for example USD or CAD.

Credit memos

An 810 can also reverse or reduce an earlier charge. In the guide that uses BIG07 values CR and DI, CR identifies a credit memo and its reference segment carries a credit reference qualifier (8V). The Stedi reference also notes a BAL segment used only when BIG07 indicates a monthly or special-handling adjustment invoice. Treat credit memos as a separate matching path: they reduce what you owe rather than add a new charge.

Reconciliation checklist

This checklist gathers the checks above in one place. Every row draws on the sources listed below; none is a universal rule.

Check	What to compare	Where it comes from
PO match	BIG04 against the PO number you issued	Buyer 810 guides (must-use in one, used in another)
Line match	IT101 against the PO line number; each line number once	Buyer 810 guide
Unit match	IT103 unit of measure against the ordering unit	Buyer 810 guide
Invoice total	TDS01 against the sum of the lines, allowing for the implied two decimals (30502 = $305.02)	Buyer 810 guides
Tax in total	Whether the TDS total includes tax, per your partner guide	Buyer 810 guide
Line count	CTT01 against the number of IT1 lines received	Stedi X12 reference; buyer guide
Segment count	SE01 against the segments in the set, counting ST and SE	Stedi X12 reference; buyer guide
Credit or debit	BIG07 (CR or DI in one guide) to route credit memos separately	Buyer 810 guide

Buyer guides differ: what to confirm

The comparisons above show the practical lesson: the same segment can be optional in the standard, must-use in one buyer’s guide and merely used in another, and the 810 version a partner uses can differ from the one shown in a reference site (the two buyer guides cited below are written to version 4010, the reference layout to 003040). Before go-live, ask the supplier or the buyer’s EDI team:

• Which implementation guide and X12 version apply to this relationship?
• Which segments, including BIG04 and IT101, are required rather than optional?
• Are taxes included in the TDS total, and which currency segment is expected?
• How are credit memos identified?
• Can a test invoice be exchanged before live invoices?

Payment timing is a separate subject, covered for medical supply accounts in net 30 terms for medical supply orders, and the documents a supplier typically provides before an account opens are listed in the vendor onboarding documentation checklist. The difference between the request and the order that precedes an invoice is explained in purchase requisition vs purchase order.

Common misunderstandings

• “The 810 is the same everywhere.” The standard defines the transaction set; each buyer’s guide narrows it.
• “An invoice total of 30502 is thirty thousand dollars.” Under the implied-decimal convention in the example above it is $305.02.
• “CTT01 counts every segment.” It counts IT1 line items; SE01 is the segment count.
• “An 810 only bills.” It can also carry credit memos, depending on BIG07 and the partner guide.

FAQ

What is an EDI 810?

It is the X12 invoice transaction set, which X12 describes as usable for the customary billing of goods and services provided.

Which PO number does an 810 carry?

The two buyer guides cited below place the purchase order number in BIG04 and the PO date in BIG03.

Is the 810 sent by the buyer or the supplier?

The supplier sends it; it is commonly the reply to a buyer’s EDI 850 purchase order.

Sources

• X12, Transaction Sets, x12.org/products/transaction-sets, checked 2026-11-03.
• Stedi, X12 003040 810 Invoice reference, stedi.com/edi/x12-003040/810, checked 2026-11-03. A reference site, not the standards body.
• Insight Direct USA, EDI 810 Vendor Guidelines v3.1 (version 4010, modified 2025-11-24), insight.com 810 guideline PDF, checked 2026-11-03. One buyer’s rules.
• Cooper Standard, CS EDI Specification 810 V1 (version 4010), cooperstandard.com 810 specification PDF, checked 2026-11-03. One buyer’s rules.