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 women who had a recorded diagnosis of deep - vein thrombosis , venous thrombosis not otherwise specified , or pulmonary embolus during the study period , and who had been treated with an anticoagulant were identified as potential cases of VTE .
### Output Text:
All women who had a recorded diagnosis of deep - vein thrombosis , venous thrombosis not otherwise specified , or pulmonary embolus during the study period , and who had been treated with an anticoagulant were identified as potential cases of VTE . 