Final answer:
The action of sharing patient information without authorization violates HIPAA, which is designed to protect patient privacy rights and maintain confidentiality of health records.
Step-by-step explanation:
The medical assistant's action of providing confidential information about a patient to a family member without checking the release of information form violates the Health Insurance Portability and Accountability Act (HIPAA). HIPAA requires entities like healthcare providers to protect patient health information and maintain strict confidentiality, except in specific circumstances where disclosure is allowed. Disclosing such sensitive information without a patient's consent or without legal authorization directly contravenes HIPAA's privacy rule, which aims to safeguard patient privacy rights.