Clinical nurse specialist
A clinical nurse specialist (CNS) is an advanced practice registered nurse, with graduate preparation (earned master's or doctorate) from a program that prepares CNSs. According to the APRN Consensus Model for Regulation (2008), "The CNS has a unique APRN role to integrate care across the continuum and through three spheres of influence: patient, nurse, system. The three spheres are overlapping and interrelated but each sphere possesses a distinctive focus. In each of the spheres of influence, the primary goal of the CNS is continuous improvement of patient outcomes and nursing care. Key elements of CNS practice are to create environments through mentoring and (p. 8) system changes that empower nurses to develop caring, evidence-based practices to alleviate patient distress, facilitate ethical decision-making, and respond to diversity. The CNS is responsible and accountable for diagnosis and treatment of health/illness states, disease management, health promotion, and prevention of illness and risk behaviors among individuals, families, groups, and communities." (p. 9). CNSs are clinical experts in a specialized area of nursing practice and in the delivery of evidence-based nursing interventions.
CNSs work with other nurses to advance their nursing practices, improve outcomes, and provide clinical expertise to effect system-wide changes to improve programs of care. CNSs work in specialties that are defined by one of the following categories:
- Population (e.g. pediatrics, geriatrics, women’s health)
- Setting (e.g. critical care, emergency department, long-term care)
- Disease or Medical Subspecialty (e.g. diabetes, oncology, palliative)
- Type of Care (e.g. psychiatric, rehabilitation)
- Type of Problem (e.g. pain, wounds, palliative)
Spheres of influence 
There are three domains of CNS practice, known as the three spheres of influence (NACNS 2004):
- Nursing personnel
- System (healthcare system)
The three spheres are overlapping and interrelated, but each sphere possesses a distinctive focus. In each of the spheres of influence, the primary goal of the CNS is continuous improvement of patient outcomes and nursing care.
Core competencies 
Within the three spheres of CNS practice, Sparacino (2005) identified seven core competencies:
- Direct clinical practice includes expertise in advanced assessment, implementing nursing care, and evaluating outcomes.
- Expert coaching and guidance encompasses modeling clinical expertise while helping nurses integrate new evidence into practice. It also means providing education or teaching skills to patients and family.
- Collaboration focuses on multidisciplinary team building.
- Consultation involves reviewing alternative approaches and implementing planned change.
- Research involves interpreting and using research, evaluating practice, and collaborating in research.
- Clinical and professional leadership involves responsibility for innovation and change in the patient care system.
- Ethical decision-making involves influence in negotiating moral dilemmas, allocating resources, directing patient care and access to care.
Although these core competencies have been described in the literature they are not validated through a review process that is objective and decisive. They are the opinion of some within the profession. A set of core competencies has now been described and validated through a consensus process (2008) that clearly defines the spheres of influence, the synergy model and the competencies as defined by Sparacino (2005). These core competencies are now expected to be used in all educational programs and will be revised in the coming years in order to be maintained as current and reflective of practice.
International perspectives 
Historically, in North America, the CNS role developed within the acute care (hospital) setting. Currently, in addition to the traditional acute care setting, CNSs practice in a variety of non-acute care settings.
In the Australian Health System, however, a clinical nurse specialist refers to a promotional position, rather than a qualification.
See also 
- Advanced Practice Nurse
- Clinical nurse leader
- Doctor of Nursing Practice
- Master of Science in Nursing
- Nurse Practitioner
- APRN Consensus Work Group & the National Council of State Boards of Nursing APRN Advisory Committee (7 July 2008). "Consensus Model for APRN Regulation: Licensure, Accreditation, Certification & Education". APRN Joint Dialogue Group Report. Retrieved 25 January 2012.
- Newhouse, Robin; Julie Stanik-Hutt, Kathleen M. White, Meg Johantgen, Eric B. Bass, George Zangaro, Renee F. Wilson, Lily Fountain, Donald M. Steinwachs, Lou Heindel, Jonathan P. Weiner (September/October 2011). "Advanced Practice Nurse Outcomes: 1990-2008: A Systematic Review". Nursing Economic$ 29 (5). Retrieved 16 August 2011.
- Sparacino, P. S. A. (2005). The clinical nurse specialist. In A. B. Hamric, J. A. Spross & C. M. Hanson (Eds.), Advanced practice nursing: An integrative approach (3rd ed., pp. 415–446). St. Louis: Elsevier