ArithMedic

ArithMedic is a free, open-source, FHIR-native medical calculation API.

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📁 Project Structure

arithmedic
├── api                 # API mappings
│   ├── egfr
│   └── __init__.py
├── calculators         # Calculator logic
│   ├── egfr
│   └── __init__.py
├── fhir_mappings       # fhir.resources schemas for I/O validation
│   └── egfr
├── schemas             # Pydantic schemas for I/O validation
│   ├── egfr
│   └── __init__.py
├── templates           # HTML templates
│   ├── egfr
│   ├── base.html
│   └── index.html
├── tests               # pytest test files
│   ├── calculators
│   └── __init__.py
├── README.md
├── __init__.py
├── conftest.py
├── main.py
├── pyproject.toml
└── requirements.txt

🛠️ Technical Architecture

The project uses a modular design with the following main components:

• API (main.py, api/): Provides API interface
• Calculator Logic (calculators/): Medical calculators separated by category and specific calculator.
• FHIR mappings (fhir_mappings/): I/O mappings to FHIR standard.
• Pydantic Schemas (schemas/): I/O validation.
• HTML Templates (templates/): HTML templates for landing page and example web calculator.
• Test Suite (tests/): Tests and functionality verification for API, calculators, FHIR mappings, schemas, and templates.

Example:

Request body:

curl -X 'POST' \
  'https://www.arithmedic.eu/fhir/egfr/ckd-epi-2021' \
  -H 'accept: application/json' \
  -H 'Content-Type: application/json' \
  -d '{
  "resourceType": "Parameters",
  "parameter": [
    {
      "name": "serum-creatinine",
      "valueQuantity": {
        "value": 88,
        "unit": "umol/L"
      }
    },
    {
      "name": "age",
      "valueInteger": 65
    },
    {
      "name": "sex",
      "valueCode": "female"
    }
  ]
}'

Response body:

{
  "resourceType": "Parameters",
  "parameter": [
    {
      "name": "egfr",
      "valueQuantity": {
        "value": 63,
        "unit": "mL/min/1.73m2",
        "system": "http://unitsofmeasure.org",
        "code": "mL/min/{1.73_m2}"
      }
    },
    {
      "name": "ckd-stage-code",
      "valueCode": "G2"
    },
    {
      "name": "ckd-stage-description",
      "valueString": "Mildly decreased (60–89)"
    },
    {
      "name": "formula",
      "valueString": "2021 CKD-EPI Creatinine"
    },
    {
      "name": "reference",
      "valueUri": "https://doi.org/10.1056/NEJMoa2102953"
    }
  ]
}