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: Patients were admitted to the hospital for measurement of lithium level , creatinine clearance , urine volume , and maximum osmolality .
### Output Text:
Patients were admitted to the hospital for measurement of <span class="chemical">lithium</span> level , <span class="chemical">creatinine</span> clearance , urine volume , and maximum osmolality . 