SKS

SKS, the Danish national healthcare classification system maintained by Sundhedsdatastyrelsen (the Danish Health Data Authority), spans diagnoses, surgical and non-surgical procedures, examinations, treatments, functioning and disability, and supplementary classifications across Danish hospitals and healthcare services. The diagnosis codes (main group D) are based on ICD-10, while the remaining main groups cover the rest of the Danish healthcare coding domains.

Because SKS combines diagnosis and procedure codes in one system, you can use Code filtering to restrict predictions to one code type depending on your use case.

Quick start

Predict codes integration: SKS

Request: code prediction system identifier, sks

const response = await client.codes.predict({
  system: ["sks"],
  context: [{ type: "text", text: "Patient indlagt med akut hjerteinsufficiens og type 2-diabetes. Røntgen af højre knæ udført." }],
});

import requests

# Replace these with your values
ENVIRONMENT = "<eu-or-us>"
TENANT = "<your-tenant-name>"
TOKEN = "<your-access-token>"

response = requests.post(
    f"https://api.{ENVIRONMENT}.corti.app/v2/tools/coding/",
    headers={
        "Authorization": f"Bearer {TOKEN}",
        "Tenant-Name": TENANT,
        "Content-Type": "application/json",
    },
    json={
        "system": ["sks"],
        "context": [{"type": "text", "text": "Patient indlagt med akut hjerteinsufficiens og type 2-diabetes. Røntgen af højre knæ udført."}],
    },
)
response.raise_for_status()
print(response.json())

# Replace these with your values
ENVIRONMENT="<eu-or-us>"
TENANT="<your-tenant-name>"
TOKEN="<your-access-token>"

curl -X POST "https://api.${ENVIRONMENT}.corti.app/v2/tools/coding/" \
  -H "Authorization: Bearer ${TOKEN}" \
  -H "Tenant-Name: ${TENANT}" \
  -H "Content-Type: application/json" \
  -d '{
    "system": ["sks"],
    "context": [{"type": "text", "text": "Patient indlagt med akut hjerteinsufficiens og type 2-diabetes. Røntgen af højre knæ udført."}]
  }'

Response: both diagnosis and procedure codes are returned

json

{
  "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
        }
      ]
    },
    {
      "system": "sks",
      "code": "UXRG25+TUL1",
      "display": "Røntgenundersøgelse af knæ, højre",
      "evidences": [
        {
          "contextIndex": 0,
          "text": "Røntgen af højre knæ",
          "start": 64,
          "end": 84
        }
      ]
    }
  ],
  "candidates": [],
  "usageInfo": {
    "creditsConsumed": 1.5
  }
}

API reference →

Filter by code type

Because SKS combines diagnosis and procedure codes in one system, you can use Code filtering to restrict predictions to one code type. The is-a operator on the code property matches a prefix and all its descendants in the SKS hierarchy.

Diagnosis only: filter with is-a: "D". See ICD-10 → Denmark (SKS) for more information.
Procedure only: filter with is-a: ["K", "UX", "B", "Z", "W", "N"]. See Procedure Codes → Denmark (SKS) for more information.

Supported code groups

SKS is organized into main groups (hovedgrupper), each covering a specific domain of Danish healthcare coding. The table below lists all main groups and indicates which are currently supported.

Code	Main group	Description	Supported
A	Administrative conditions	Administrative conditions and interventions. Contains few codes beyond personnel classification.	No
B	Treatment and Care Classification	Danish classification of non-surgical treatment, care, and prophylaxis.	Yes
D	Classification of diseases and health-related conditions	The Danish version of WHO’s ICD-10. Codes for diagnoses, symptoms, health problems, and reasons for patient contact.	Yes
E	Classification of external causes of injury	Danish version of the Nordic accident classification. Records circumstances of accidents and suicide attempts.	No
F	Classification of functioning, disability, and health	Danish version of WHO’s ICF. Systematic description of patient functioning and disability.	No
K	Classification of surgical procedures	Danish version of NCSP (Nordic Classification of Surgical Procedures). Codes for surgical procedures.	Yes
M	ATC drug classification	Danish translation of WHO’s ATC system. Used as supplementary codes to specify a diagnosis or procedure.	No
N	Anesthesia, intensive care, pre-hospital	Danish classification of anesthesia procedures.	Yes
R	Result reporting and individual results	Classifications for reporting results to LPR (the National Patient Registry).	No
U	Classification of examinations	Non-surgical examinations, including clinical examinations. Only the UX subgroup (radiological procedures) is supported.	Partial (UX)
W	Classification of clinical physiology and nuclear medicine	Danish classification of clinical physiology and nuclear medicine examinations.	Yes
Z	Supplementary codes and miscellaneous procedures	Various supplementary classifications. The ZZ area is used for miscellaneous procedure codes.	Yes

SKS background

Code structure

SKS combines diagnosis and procedure codes in a single system. Each code is prefixed by a group letter that identifies the main classification.

Diagnosis codes

Diagnosis codes use a D prefix followed by an ICD-10 code. They follow the same hierarchical structure as ICD-10 with the Danish prefix convention.

Example	Description
`DA000`	Cholera caused by Vibrio cholerae
`DE119`	Type 2 diabetes without complications
`DI509`	Heart failure, unspecified

Procedure codes

Procedure codes span multiple groups, each identified by a letter prefix:

Prefix	Group	Example	Description
`K`	Surgical procedures	`KNGB40`	Primary cemented total knee arthroplasty
`UX`	Examinations (radiology)	`UXRG25`	X-ray of the knee
`B`	Treatment and care	`BJFD00`	Acute hemodialysis
`N`	Anesthesia and intensive care	`NAAC`	General anesthesia
`W`	Clinical physiology and nuclear medicine	`WBBGS25XX`	Bone marrow scintigraphy
`Z`	Supplementary and miscellaneous procedures	`ZZ3925`	EKG

Lateral modifiers

SKS codes can carry modifier codes (tillægskoder, til group) to indicate laterality and contrast. Modifiers are optional and attached only when clinically relevant. Sundhedsdatastyrelsen maintains official LPR3 code lists that define which base codes should receive modifiers: diag.lateral and proc.lateral for obligatory laterality, proc.kontrast for obligatory contrast. Codes not in these lists can still receive modifiers voluntarily when the clinical text supports it. Codes whose display text implies bilateral (e.g., “dobbeltsidig”, “bilateral”) are excluded and never receive laterality modifiers. Modifiers are appended to the base code with a + separator; there is no separate modifiers field on the response.

Modifier	Meaning	Danish	Applies to
`TUL1`	Right-sided	højresidig	Diagnosis and procedure codes
`TUL2`	Left-sided	venstresidig	Diagnosis and procedure codes
`TUL3`	Bilateral	dobbeltsidig	Diagnosis codes only (procedures return the same base code twice, once with `TUL1` and once with `TUL2`)
`TUL7`	Side cannot be specified	side kan ikke angives	Diagnosis codes only
`UXZ11`	Without contrast	uden kontrast	Procedure codes only
`UXZ12`	Both with and without contrast	både med og uden kontrast	Procedure codes only

TUL3 (bilateral) is not used on procedure codes. A bilateral procedure returns two separate codes: one with TUL1 (right) and one with TUL2 (left). For example, a bilateral knee X-ray appears as UXRG25+TUL1 and UXRG25+TUL2. Other modifiers (such as contrast) are preserved on both entries. On diagnosis codes, TUL3 remains a single code.

Examples

Code	Display
`KNGB40+TUL1`	Total knee arthroplasty, right
`UXRG25+TUL1`	X-ray of the knee, right
`UXRG25+TUL1+UXZ11`	X-ray of the knee, right, without contrast
`DC436A+TUL3`	Melanoma, shoulder, bilateral (diagnosis)

Please contact us if you need further support in your SKS integration.

Clinical Text Generation

Medical Coding

FHIR Extraction

Clinical Assistant

Quick start

Filter by code type

Supported code groups

SKS background

Code structure

Diagnosis codes

Procedure codes

Lateral modifiers

Examples