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: Biochemically , LA was elevated ( 8 . 5 + / - 2 . 0 mM ) .
### Output Text:
Biochemically , <span class="chemical">LA</span> was elevated ( 8 . 5 + / - 2 . 0 mM ) . 