ISO/IEC指南28:2004给出了特定产品认证体系的一般指南。 本标准适用于第三方产品认证体系，通过对产品样品的初始测试、对所涉及的质量体系的评估和监督，以及对从工厂或公开市场获取的产品样品进行的测试监督，或两者兼而有之，来确定产品是否符合规定的要求。ISO/IEC指南28:2004阐述了合格标志的使用条件和颁发合格证书的条件。

ISO/IEC Guide 28:2004 gives general guidelines for a specific product certification system. It is applicable to a third-party product certification system for determining the conformity of a product with specified requirements through initial testing of samples of the product, assessment and surveillance of the involved quality system, and surveillance by testing of product samples taken from the factory or the open market, or both. ISO/IEC Guide 28:2004 addresses conditions for use of a mark of conformity and conditions for granting a certificate of conformity.