Duties of PNs and LVNs vary, depending on their work setting and the state in which they work. For example, they may reinforce teaching done by registered nurses regarding how family members should care for a relative; help to deliver, care for, and feed infants; collect samples for testing and do routine laboratory tests; or feed patients who need help eating.

PNs and LVNs may be limited to doing certain tasks, depending on the state where they work. For example, in some states, PNs with proper training can give medication or start intravenous (IV) drips, but in other states PNs cannot perform these tasks. State regulations also govern the extent to which PNs and LVNs must be directly supervised. For example, an PN may provide certain forms of care only with instructions from a registered nurse.

In some states, experienced licensed practical and licensed vocational nurses supervise and direct other PNs or LVNs and unlicensed medical staff.