If your employer provides the employee's medical insurance, is it lawful or mandatory for the medical insurance company to notify the employer that the employee takes medication used for HIV positive patients?

The insurance company or administrator can only release information to the employer to the extent needed to administer the plan. Therefore, as part of renewal, the administrator and/or insurer could release information about the costs related to certain illnesses but not who has those illnesses. If it is a self-insured plan and there is a claim denial, there could be situations, depending on the plan design, where information is made avaialable to an employer specific to an individual but only to the extent needed for administration of the plan.