In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Laboratory test findings on admission were notable only for a flecainide plasma concentration of 1360 microg / L ( reference range 200 - 1000 ) .
### Output Text:
Laboratory test findings on admission were notable only for a <span class="chemical">flecainide</span> plasma concentration of 1360 microg / L ( reference range 200 - 1000 ) . 