{
  "esr": {
    "sources": {
      "eicu_demo": [
        {
          "ids": "eryth",
          "table": "lab",
          "sub_var": "labname"
        }
      ]
    }
  },
  "fgn": {
    "sources": {
      "mimic_demo": [
        {
          "ids": 12345,
          "table": "labevents",
          "sub_var": "itemid"
        }
      ]
    }
  },
  "foo": {
    "unit": "mg/dL",
    "min": 0,
    "max": 1500,
    "description": "foo concept",
    "category": "bar category",
    "sources": {
      "eicu_demo": [
        {
          "ids": "foo",
          "table": "lab",
          "sub_var": "labname"
        }
      ],
      "mimic_demo": [
        {
          "ids": 12345,
          "table": "labevents",
          "sub_var": "itemid"
        }
      ]
    }
  }
}
