# BR-65 Item classification identifier must have a scheme identifier

The Item classification identifier (BT-158) shall have a Scheme identifier that names the classification scheme used.

## Problem Description

The Item classification identifier (BT-158) shall have a Scheme identifier that names the classification scheme used.

> **ERROR**: XRechnung 3.0

## Context and Significance

This rule comes from the EN16931 core semantic model enforced by the KoSIT XRechnung 3.0.2 Schematron, ensuring invoices carry the mandatory data needed for automated processing.

## Solution

Set the listID attribute on cac:CommodityClassification/cbc:ItemClassificationCode using a UNCL7143 code, for example TST for UNSPCC or ST for a supplier scheme.

- validate
- convert

## Valid Examples

- BT-158 = 65010000 with listID="STI" (classification scheme)

## Invalid Examples

- BT-158 classification code present but with no listID attribute

## Code Examples

### Valid XML
```
<cac:Item>
  <cac:CommodityClassification>
    <cbc:ItemClassificationCode listID="STI">65010000</cbc:ItemClassificationCode>
  </cac:CommodityClassification>
</cac:Item>
```

### Invalid XML
```
<cac:Item>
  <cac:CommodityClassification>
    <cbc:ItemClassificationCode>65010000</cbc:ItemClassificationCode>
  </cac:CommodityClassification>
</cac:Item>
```

## Affected Fields

- [BT-158 Item classification identifier](/resources/xrechnung/bt-158-item-standard-identifier-scheme)

## Related Rules

- [BR-64](/resources/kosit-validator-errors/br-64-item-standard-identifier-scheme-required)

## Validation Tools

- [Official KoSIT Validator](https://erechnungsvalidator.service-bw.de/): Validate your XRechnung files against all BR-DE rules.
- [Convert PDF to XRechnung](/pdf-to-xrechnung): Automatic validation error fixes when converting.

## Related Resources

- [Official Specification](https://xeinkauf.de/xrechnung/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)
- [Complete Error List](/resources/kosit-validator-errors): Overview of all German XRechnung validation rules.