The concepts of confidentiality and privilege certainly have some similarities but there are crucial differences of which clinicians should be aware.

Confidentiality─

Confidentiality is an ethical standard of professional conduct that obligates a professional not to discuss information about a client with anyone, except under certain circumstances agreed to by both the source (client) and the professional (listener).

In Washington State, licensed mental health counselors are ethically and legally bound to keep confidential that which they learn in the course of providing their clinical services.
 

The Myth of Confidentiality

Confidentiality Standard & Exceptions for Masters-Level Licensed Counselors in Washington State
 

Privileged Communication ─

Privileged Communication is a legal concept that defines a right owned by the source (client). It protects individuals who participate in special relationships from having their confidences disclosed in court without their permission.

Currently in Washington State, only those mental health clients who see psychologists and psychiatrists have guaranteed privileged communication.

All mental health clinicians are subject to mandatory reporting laws that require the clinician to report suspected abuse or neglect of a child or a vulnerable adult.  

Clinicians are also legally and ethically bound to intervene to prevent death or harm of either the client or an identifiable victim.

More on Privileged Communication

Privileged Communication in Washington State 

Privilege for Psychologists & Their Patients
 

Other Resources─

The 'Lectric Law Library's Lexicon On Privileged Communication

The Limits of Privilege: The Developing Scope of Federal Psychotherapist-Patient Privilege Law

Legal Loopholes Could Limit Psychotherapist-Privilege Victory