Variations in how physicians describe diagnoses and order laboratory tests, as well as imprecisions in the coding used for payer billing, make it difficult for an automated systems such as Google Health to create an accurate health record from an individual’s existing health records.
A Personal Health Record should in general facilitate increased safety and the quality of care you receive across multiple providers, and especially in an emergent care setting in which the attending physician may know next to nothing about your medical history. But as the article points out, a Personal Health Record that is full of errors may hurt you more than it helps you.
My personal view is that PHRs are definitely a step in the right direction, and over time they will probably become a mainstay in a new era of efficient and quality healtcare delivery. But early adopters of Personal Health Records–whether created through Google Health or another service–should proceed with caution.