> 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-expression-constraint-language/appendices/appendix-a-examples-of-valid-expressions/a1-simple-expression-constraints-valid-expressions.md).

# Simple Expression Constraints - Valid Expressions

<table data-full-width="true"><thead><tr><th width="181.33984375">Expression Constraint</th><th width="239.7890625">Precoordinated</th><th>Postcoordinated</th></tr></thead><tbody><tr><td><code>404684003 | Clinical finding|</code></td><td><code>404684003 | Clinical finding|</code></td><td><em>(none)</em></td></tr><tr><td><code>&#x3C; 404684003 | Clinical finding|</code></td><td><code>64572001 | Disease|</code></td><td><code>404684003 | Clinical finding| : 363698007 | Finding site| = 80891009 | Heart structure|</code></td></tr><tr><td><code>&#x3C;&#x3C; 73211009 | Diabetes mellitus|</code></td><td><code>56265001 | Heart disease</code><br><br><code>46635009 | Diabetes mellitus type |</code><br><br><code>105401000119101 | Diabetes mellitus due to pancreatic injury|</code></td><td><code>73211009 | Diabetes mellitus| : 42752001 | Due to| = 61823004 | Injury of pancreas|</code></td></tr><tr><td><code>&#x3C;! 404684003 | Clinical finding|</code></td><td><p><code>64572001 | Disease|</code><br></p><p><br><code>267038008 | Edema|</code></p></td><td><p><code>404684003 | Clinical finding| : 116676008 | Associated morphology| = 79654002 | Edema|</code><br><br>> 40541001 | Acute pulmonary edema|</p><p><br>111273006 | Acute respiratory disease|<br><br><code>64572001 | Disease| :</code> <br><code>116676008 | Associated morphology| = 79654002 | Edema| ,</code> <br><code>363698007 | Finding site| = 39607008 | Lung structure|</code></p></td></tr><tr><td><code>>> 40541001 | Acute pulmonary edema|</code></td><td><code>40541001 | Acute pulmonary edema|</code></td><td><code>64572001 | Disease| : 263502005 | Clinical course| = 424124008 | Sudden onset AND/OR short duration| , { 116676008 | Associated morphology| = 40829002 | Acute edema| , 363698007 | Finding site| = 39607008 | Lung structure| }</code><br>111273006 | Acute respiratory disease|<br>404684003 | Clinical finding|<br>138875005 | SNOMED CT concept|</td></tr><tr><td><code>>! 40541001 | Acute pulmonary edema|</code></td><td><code>111273006 | Acute respiratory disease|</code><br><br><code>19242006 | Pulmonary edema|</code></td><td><code>19829001 | Disorder of lung| : {</code> <br><code>116676008 | Associated morphology| = 79654002 | Edema| ,</code> <br><code>363698007 | Finding site| = 39607008 | Lung structure| }</code></td></tr><tr><td><code>^ 700043003 | Example problem list concepts reference set|</code></td><td><code>394659003 | Acute coronary syndrome|</code></td><td><p><code>194828000 | Angina|</code></p><p><br><code>29857009 | Chest pain|</code></p></td></tr><tr><td><code>*</code></td><td><code>138875005 | SNOMED CT concept|</code><br><br><code>404684003 | Clinical finding| : 363698007 | Finding site| = 80891009 | Heart structure|</code></td><td><p><code>404684003 | Clinical finding|</code></p><p><br><code>71388002 | Procedure| : 405813007 | Procedure site - Direct| = 66754008 | Appendix structure|</code></p><p></p><p><code>322236009 | Paracetamol 500mg tablet|</code></p><p></p><p><code>373873005 | Pharmaceutical / biologic product| : { 127489000 | Has active ingredient| = 412031009 | Paracetamol or derivative| }</code></p></td></tr></tbody></table>

{% hint style="info" %}

* Where necessary, these examples make some assumptions about the membership of the example reference sets.
* Please note that this makes the assumption that the given expression constraint is executed against a finite set of expressions that has been pre-classified (e.g. in an expression repository), and that after classification there are no intermediate expressions between this expression and 404684003 |Clinical finding|.
* Please note that this makes the assumption that the given expression constraint is executed against a finite set of expressions that has been pre-classified (e.g. in an expression repository), and that after classification there are no intermediate expressions between 40541001 |Acute pulmonary edema| and this expressio
  {% endhint %}

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