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: Data suggest that this sensitive hemoglobin assay is useful for ICH detection , and that a model with a small ICH induced with a low - dose collagenase should be used for evaluation of drugs that may affect ICH .
### Output Text:
Data suggest that this sensitive hemoglobin assay is useful for ICH detection , and that a model with a small ICH induced with a low - dose collagenase should be used for evaluation of drugs that may affect ICH . 