> ## Documentation Index
> Fetch the complete documentation index at: https://docs.corti.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# SKS diagnosis codes

> Filter SKS predictions to diagnosis codes using the D prefix hierarchy

SKS is Denmark's national coding system. Diagnosis codes use the **D** prefix and follow the ICD-10 hierarchy with Danish conventions.

> [!TIP]
>
> See the [SKS overview](https://docs.corti.ai/coding/sks.md) for the full system description, code structure, and supported groups.

***

## Filter by diagnosis codes

Use the `is-a` operator with `"D"` on the `code` property to restrict predictions to diagnosis codes. Because SKS uses a prefix-based hierarchy, `is-a: "D"` matches the D group itself and all descendant codes (every code starting with `D`).

**Request**: restrict predictions to SKS diagnosis codes (D group) using `is-a`:

```json theme={null}
{
  "system": ["sks"],
  "context": [
    { "type": "text", "text": "Patient indlagt med akut hjerteinsufficiens og type 2-diabetes. Røntgen af højre knæ udført." }
  ],
  "filters": [
    {
      "systemId": "sks",
      "include": {
        "conditions": [
          { "property": "code", "op": "is-a", "value": "D" }
        ]
      }
    }
  ]
}
```

**Response**: only D-prefixed diagnosis codes are returned:

```json theme={null}
{
  "codes": [
    {
      "system": "sks",
      "code": "DI509",
      "display": "Hjertesvigt UNS",
      "evidences": [
        {
          "contextIndex": 0,
          "text": "akut hjerteinsufficiens",
          "start": 20,
          "end": 43
        }
      ]
    },
    {
      "system": "sks",
      "code": "DE119",
      "display": "Type 2-diabetes uden komplikationer",
      "evidences": [
        {
          "contextIndex": 0,
          "text": "type 2-diabetes",
          "start": 47,
          "end": 62
        }
      ]
    }
  ],
  "candidates": [],
  "usageInfo": {
    "creditsConsumed": 1.5
  }
}
```

[API reference →](https://docs.corti.ai/api-reference/codes/predict-codes.md)

See [code filtering](https://docs.corti.ai/coding/code-filtering.md) for full details on filter properties, operators, and additional examples.

***

## Modifiers on diagnosis codes

Both diagnosis and procedure codes can carry modifiers (see [Lateral modifiers](https://docs.corti.ai/coding/sks.md#lateral-modifiers) for the full list). The official `diag.lateral` LPR3 code list defines which diagnosis codes must receive a lateral modifier; for example, `DC436A` (Malignt melanom i hud på skulder) is in the list. `TUL7` (side cannot be specified) is a diagnosis-only modifier with no procedure equivalent.

On diagnosis codes, `TUL3` (bilateral) remains a single code in the response, unlike procedure codes where it is not used.

| Code | Display |
| - | - |
| `DC436A+TUL1` | Melanoma, shoulder, right |
| `DC436A+TUL2` | Melanoma, shoulder, left |
| `DC436A+TUL3` | Melanoma, shoulder, bilateral |

## Related

* [SKS overview](https://docs.corti.ai/coding/sks.md): system description, code structure, lateral modifiers
* [SKS procedure codes](https://docs.corti.ai/coding/sks-procedure.md): filter to procedure codes only


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