> For the complete documentation index, see [llms.txt](https://docs.snomed.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.snomed.org/snomed-ct-specifications/snomed-ct-editorial-guide/readme/authoring/domain-specific-modeling/observable-entity/observable-entity-naming-conventions.md).

# Observable Entity Naming Conventions

## Test Observable Entity Naming Conventions

Naming conventions for the fully specified name (FSN) for observable entities and for naming evaluation procedures or observable entities that are submitted with names from the IFCC-IUPAC NPU systems are as follows:

General naming pattern: Property, Component, Direct Site

* **First: Property**
  * Property (the property type of the observable) is named first, when possible.
  * Modifier: Scale Method.
    * Scale Method refines the Property, and, therefore, precedes the action in the naming order. (Scale Method, Property)
    * Naming pattern: (Scale Method, Property), Component, Direct Site
* **Second: Component**
  * Property is named first, followed by the entity that is the value of Component, when possible.
* **Third: Direct Site**
  * Modifier: Time aspect. Time aspect provides information about the direct site and precedes it in the naming order. (Time aspect, Direct Site)
* For example,
  * 416125006 | Concentration of hemoglobin in erythrocyte (observable entity) |

{% hint style="success" %}
**Modeling screening measurements**

Measurements done by screening should be specified with *by screening method* added at the end of the description.
{% endhint %}

*Serology* and *serologic test* are ambiguous terms and should not be included in FSNs. These terms can be included in the descriptions for antibody observable or evaluation concepts but cannot be included in the preferred term. Existing content will be fixed in a future release.

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