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: On day 8 , the patient developed acute renal failure ( serum creatinine 1 . 9 mg / dL , increased from 1 . 2 mg / dL the previous day and 0 . 8 mg / dL on admission ) .
### Output Text:
On day 8 , the patient developed acute renal failure ( serum <span class="chemical">creatinine</span> 1 . 9 mg / dL , increased from 1 . 2 mg / dL the previous day and 0 . 8 mg / dL on admission ) . 