| Code | Display | Definition | 
| missing  | 
Missing | 
The search parameter returns resources that have a value or not. | 
| exact  | 
Exact | 
The search parameter returns resources that have a value that exactly matches the supplied parameter (the whole string, including casing and accents). | 
| contains  | 
Contains | 
The search parameter returns resources that include the supplied parameter value anywhere within the field being searched. | 
| not  | 
Not | 
The search parameter returns resources that do not contain a match. | 
| text  | 
Text | 
The search parameter is processed as a string that searches text associated with the code/value - either CodeableConcept.text, Coding.display, Identifier.type.text, or Reference.display. | 
| in  | 
In | 
The search parameter is a URI (relative or absolute) that identifies a value set, and the search parameter tests whether the coding is in the specified value set. | 
| not-in  | 
Not In | 
The search parameter is a URI (relative or absolute) that identifies a value set, and the search parameter tests whether the coding is not in the specified value set. | 
| below  | 
Below | 
The search parameter tests whether the value in a resource is subsumed by the specified value (is-a, or hierarchical relationships). | 
| above  | 
Above | 
The search parameter tests whether the value in a resource subsumes the specified value (is-a, or hierarchical relationships). | 
| type  | 
Type | 
The search parameter only applies to the Resource Type specified as a modifier (e.g. the modifier is not actually :type, but :Patient etc.). | 
| identifier  | 
Identifier | 
The search parameter applies to the identifier on the resource, not the reference. | 
| of-type  | 
Of Type | 
The search parameter has the format system|code|value, where the system and code refer to an Identifier.type.coding.system and .code, and match if any of the type codes match. All 3 parts must be present. | 
| code-text  | 
Code Text | 
Tests whether the textual display value in a resource (e.g., CodeableConcept.text, Coding.display, or Reference.display) matches the supplied parameter value. | 
| text-advanced  | 
Text Advanced | 
Tests whether the value in a resource matches the supplied parameter value using advanced text handling that searches text associated with the code/value - e.g., CodeableConcept.text, Coding.display, or Identifier.type.text. | 
| iterate  | 
Iterate | 
The search parameter indicates an inclusion directive (_include, _revinclude) that is applied to an included resource instead of the matching resource. |