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: The incidence of hospitalisation for TDF kidney adverse effects was high , particularly amongst patients with features of Fanconi syndrome .
### Output Text:
The incidence of hospitalisation for <span class="chemical">TDF</span> kidney adverse effects was high , particularly amongst patients with features of Fanconi syndrome . 