# BT-158-1 Item Classification Identifier Scheme Identifier

The UNTDID 7143 code of the classification scheme used in BT-158, for example HS for the Harmonised System. It is an attribute of BT-158 and is required whenever BT-158 is present (BR-65).

## Quick answer

> **Line items**: The goods or services on each invoice line, including quantities, prices, and VAT.

- [Validate XML](/en/xrechnung-validator?source=resource&bt=BT-158-1)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&bt=BT-158-1)

## In plain language

Identifies the invoiced goods or services for buyer, seller, and automated procurement or inventory matching.

## What you usually enter here

Classification scheme identifier

Typical valid values include: HS, STI

Defined by EN 16931 for invoice line item identification; mandatory item names and optional identifiers must follow the listed scheme and country code rules.

## Where the field sits

BT-158-1 belongs to the Lines part of the invoice. UBL 2.1 Syntax: Invoice › cac:InvoiceLine › cac:Item › cac:CommodityClassification › cbc:ItemClassificationCode @listID. CII (UN/CEFACT) Syntax: rsm:CrossIndustryInvoice › rsm:SupplyChainTradeTransaction › ram:IncludedSupplyChainTradeLineItem › ram:SpecifiedTradeProduct › ram:DesignatedProductClassification › ram:ClassCode @listID.

## What goes wrong often

Avoid values like: CPV

Relevant rule codes: BR-65, BR-CL-13

## Valid Examples

- HS
- STI

## Invalid Examples

- CPV

## Related Fields

- [BT-158 Item Classification Identifier](/resources/xrechnung/bt-158-item-classification-identifier)

## XML mapping and field facts

Open the technical reference if you need XML paths, validator rule codes, legal wording, or schema-specific mapping details.

### Field ID:
BT-158-1

### Data Type:
code

### Cardinality:
1..1

### Requirement:
Optional

## XML Implementation

### UBL 2.1 Syntax
```
/Invoice/cac:InvoiceLine/cac:Item/cac:CommodityClassification/cbc:ItemClassificationCode/@listID
```

### CII (UN/CEFACT) Syntax
```
/rsm:CrossIndustryInvoice/rsm:SupplyChainTradeTransaction/ram:IncludedSupplyChainTradeLineItem/ram:SpecifiedTradeProduct/ram:DesignatedProductClassification/ram:ClassCode/@listID
```

## Validation Rules

### BR-65
BR-65

### BR-CL-13
BR-CL-13

## Check whether your XRechnung sets BT-158-1 correctly

Upload the XML file to the free validator. It applies the KoSIT rules for XRechnung 3.0 and names each finding with its rule ID, for this field for example BR-CL-13, BR-65. Creating a new invoice instead? The converter checks the invoice against the same rules and shows the findings before download.

- [Validate XML](/en/xrechnung-validator)
- [Convert invoice](/en/pdf-to-xrechnung)

Free, no account needed. XML file up to 2 MB.

## Official sources and tools

- [KoSIT Validator](https://erechnungsvalidator.service-bw.de/)
- [XRechnung Standard](https://xeinkauf.de/xrechnung/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)