CodeSystem Concept Lookup

Given a code/system, or a Coding, get additional details about the concept, including definition, status, designations, and properties. One of the products of this operation is a full decomposition of a code from a structure terminology
In Aidbox this is essentially the same as search Concept by system and code
GET [base]/fhir/CodeSystem/$lookup?system=http://loinc.org&code=1963-8
equals to
GET [base]/Concept?system=http://loinc.org&code=1963-8
The only difference is response format.
With Concept Search you can do even more, than just getting one concept. For example search and filter by any concept elements. 
POST [base]/CodeSystem/$lookup
More info in official doc.
Parameters
Parameter
Type
Status
code
​code​
supported
system
​uri​
supported
version
​string​
supported
coding
​Coding​
supported
date
​dateTime​
not supported
displayLanguage
​code​
not supported
property
​code​
not supported
Examples
Available output parameters: name, display, version, designation, property
Request
Response
POST [base]/CodeSystem/$lookup
{
	"resourceType" : "Parameters",  
	"parameter" : [     
		{      
			"name" : "system",      
			"valueUri" : "http://hl7.org/fhir/goal-status"     
			
		},
		{
			"valueCoding": {     		
				"code": "accepted"
			}
		}
	]
}
{
    "resourceType": "Parameters",
    "parameter": [
        {
            "name": "display",
            "valueString": "Accepted"
        },
        {
            "name": "name",
            "valueString": "GoalStatus"
        }
    ]
}
Request
Response
GET [base]/CodeSystem/$lookup?system=http://hl7.org/fhir/v2/0003&code=RAR
or:
POST [base]/CodeSystem/$lookup
{
	"resourceType" : "Parameters",  
	"parameter" : [     
		{      
			"name" : "system",      
			"valueUri" : "http://hl7.org/fhir/v2/0003"     
			
		},
		{
			"name": "code",
			"valueCode": "RAR"
		}
	]
}
{
    "resourceType": "Parameters",
    "parameter": [
        {
            "name": "display",
            "valueString": "RAR - Pharmacy administration information query response"
        },
        {
            "name": "designation",
            "value": {
                "display": {
                    "de": "Antwort bzgl. der Behandlungs-/Darreichungsform",
                    "nl": "RAR - Medicatietoediening-informatie query antwoord"
                }
            }
        },
        {
            "name": "property",
            "value": {
                "v2-0003": {
                    "deprecationDate": "2000-11"
                }
            }
        },
        {
            "name": "name",
            "valueString": "v2 Event Type"
        }
    ]
}
CodeSystem
CodeSystem Subsumption testing
Last updated 4 months ago
Parameter	Type	Status
code	code	`supported`
system	uri	`supported`
version	string	`supported`
coding	Coding	`supported`
date	dateTime	`not supported`
displayLanguage	code	`not supported`
property	code	`not supported`