Each state has a law known as the Nurse Practice Act that legally defines the practice of registered nurses, licensed practical nurses, and advanced practice registered nurses (also called nurse practitioners). Different laws define the practice of physicians, dentists, and other health care professionals.

In Connecticut, the law describing the role of the LPN states:

• The practice of nursing by a licensed practical nurse is defined as the performing of selected tasks and sharing of responsibility under the direction of a registered nurse or an advanced practice registered nurse and within the framework of supportive and restorative care, health counseling and teaching, case finding and referral, collaborating in the implementation of the total health care regimen and executing the medical regimen under the direction of a licensed physician or dentist.
• In practice, this means that LPNs work under the supervision of a licensed professional (usually an RN) and provide basic hands-on care that helps to improve the health of generally stable patients.

In Connecticut, the law describing the role of the RN states:

• The practice of nursing by a registered nurse is defined as the process of diagnosing human responses to actual or potential health problems, providing supportive and restorative care, health counseling and teaching, case finding and referral, collaborating in the implementation of the total health care regimen, and executing the medical regimen under the direction of a licensed physician, dentist or advanced practice registered nurse.
• In practice, this means that RNs have a greater level of responsibility because they direct the care of LPNs and nurses' aides in addition to developing plans of care that they and others follow. RNs evaluate how patients' illnesses, injuries, or other health conditions affect them and those close to them; and think ahead to identify and help people who are at risk for a variety of health conditions. RNs also provide hands-on care, typically caring for patients whose conditions are not stable, or patients whose needs are more complex than those cared for by an LPN. Because of these added responsibilities, RN salaries are higher than LPN salaries.