ISO/TS 21091:2005定义了使用X.500框架的医疗保健目录服务的最低规范。本技术规范提供了支持公共网络上医疗保健信息安全交换所需的公共目录信息和服务。ISO/TS 21091:2005从社区角度阐述了健康目录，以支持企业间、司法管辖区间和国际医疗保健沟通。 ISO/TS 21091:2005还支持目录服务，旨在支持卫生专业人员和组织以及患者/消费者的身份识别。后一种服务包括有时被称为主患者指数的方面。 health care目录将仅支持标准LDAP客户端搜索。具体实施指南、搜索标准和支持不在本文件范围内。

ISO/TS 21091:2005 defines minimal specifications for directory services for health care using the X.500 framework. This Technical Specification provides the common directory information and services needed to support the secure exchange of health care information over public networks. ISO/TS 21091:2005 addresses the health directory from a community perspective in anticipation of supporting inter-enterprise, inter-jurisdiction and international health care communications. ISO/TS 21091:2005 also supports directory services aiming to support identification of health professionals and organizations and the patients/consumers. The latter services include aspects sometimes referred to as master patient indices. The health care directory will only support standard LDAP Client searches. Specific implementation guidance, search criteria and support are out of scope of this document.