This code system http://loinc.org defines the following codes:

JSON

{
    "resourceType": "CodeSystem",
    "id": "Zqli4zo-1535366955840",
    "meta": {
        "versionId": "1536357572607",
        "lastUpdated": "2018-09-07T21:59:32.607+00:00"
    },
    "url": "http://loinc.org",
    "version": "1.0.0",
    "name": "Loinc CodeSystem",
    "status": "active",
    "experimental": false,
    "date": "2018-08-24T07:44:43+10:00",
    "publisher": "Loinc",
    "description": "Loinc CodeSystem",
    "caseSensitive": true,
    "content": "complete",
    "concept":  [
        {
            "code": "41653-7",
            "display": "Glucose [Mass/volume] in Capillary blood by Glucometer"
        },
        {
            "code": "2339-0",
            "display": "Glucose [Mass/volume] in Blood"
        },
        {
            "code": "9059-7",
            "display": "Carbohydrate intake Estimated"
        },
        {
            "code": "9060-5",
            "display": "Carbohydrate intake Measured"
        }
    ]
}