The culprit, as it turned out, was the billing codes and associated descriptions in those records.
"These descriptions, from the International Classification of Diseases (ICD-9), often do not accurately describe a patient because the right ICD-9 code may not exist," Roni Zeiger, product manager for Google Health, wrote in a blog posting. "So the doctor or hospital administrator chooses something that is 'close enough' for billing purposes. In other cases, the assigned code is precisely what the doctor is trying to rule out, and if the patient turns out not to have that often scary diagnosis, it is still associated with their record."
When Google Health replicated those billing codes, though, it also assigned deBronkart some phantom conditions. "We're also glad this happened," Zeiger wrote, "because we and many others now better understand the limitations of certain types of health data and we are working with partners to improve the quality of the data before it gets to Google Health and our users." Nonetheless, he added, "We are more committed than ever to putting consumers in charge of their own health information."
