The ER is usually for medical emergencies or acute issues which are likely to require blood tests or imaging or more invasive medical interventions. These patients tend to be more unwell and have a higher chance of requiring the need for admission to hospital. Often the diagnosis or management of these patients take longer and they may require a bed.
Urgent care is for acute but minor issues, which are problems that can usually be managed by general practitioners without requiring blood tests or invasive medical interventions. Whilst, these patients may also be unwell, they are stable and unlikely to deteriorate. The issues they present with can often be managed and diagnosed in a shorter period of time and these patients are less likely to require hospital admission.