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: Before angiography , intradermal or intravenous indocyanine green testing , or both was performed at 13 of 15 institutions .
### Output Text:
Before angiography , intradermal or intravenous <span class="chemical">indocyanine green</span> testing , or both was performed at 13 of 15 institutions . 