Under State medical certification and licensing laws, physicians are obliged to respect patients' privacy. But, contrary to widespread public belief, the physician–patient confidentiality privilege relates more to whether courts can force disclosure, than to whether physicians may reveal data to insurance companies or employers. Tort law provides partial reinforcement of obligations to confidentiality in healthcare relationships.
Weaker licensure laws cover nurses, speech therapists, psychologists, clinical laboratory personnel, and some other healthcare professionals. Nominally, under their licenses and their contracts with healthcare institutions, doctors and some other practitioners are responsible for the actions of persons working under their supervision. (But in actual practice, how firmly do they supervise?) These laws vary considerably.