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: Only 1 of the 4 , 446 liver function tests ( 0 . 02 % ) , a gamma glutamyl transferase , was greater than or equal to 3 times the upper normal limit .
### Output Text:
Only 1 of the 4 , 446 liver function tests ( 0 . 02 % ) , a gamma glutamyl transferase , was greater than or equal to 3 times the upper normal limit . 