I work as a CNA in the ER and we do basically everything that JessicRN mentioned: We do most of the blood draws for labs, the ECGs, vital signs, collect urine/sputum/stool samples for testing, assist patients to/from the bathroom, do one to one watch with some of the psych patients, change beds, dress and clean up patients as needed, foley care, BG monitoring, guaiacs, bring them food/drinks, CPR/chest compressions, NG tube care, ostomy care, fetch supplies and dressing materials for the MDs or RNs, etc. We don't clean rooms or escort patients to Xray or CT scan or MRI, we have other staff that does that. I think it just depends on where you work as to what your duties may be.