Regional and national health care data repositories.

Efforts are underway to define a national framework for secondary analysis of health-related data. In the meantime, regional health databases have been constructed using insurance claims data, clinical data from single large health care providers, clinical data from multiple collaborating health care providers, and public health data. Large-scale survey data also are available in government databases. Clinical laboratory results are an important component of all these databases because they can provide validation for manually assigned diagnostic and procedure codes and can support inference of key information not provided by coding, such as severity of disease and prevalence of risk factors.