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: Early recognition that incorporates the clinical and serologic clues is paramount to timely institution of treatment , as its delay may result in catastrophic outcomes .
### Output Text:
Early recognition that incorporates the clinical and serologic clues is paramount to timely institution of treatment , as its delay may result in catastrophic outcomes . 