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: All patients were also tested for liver enzymes , anti - HCV , HBeAg , and anti - HBe .
### Output Text:
All patients were also tested for liver enzymes , anti - HCV , <span class="chemical">HBeAg</span> , and anti - HBe . 