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: Antibodies suggested to be of the IgM class were detected in all 3 patients with hematological disorders .
### Output Text:
Antibodies suggested to be of the IgM class were detected in all 3 patients with hematological disorders . 