The Clinical Case Registries (CCR) replaced the former Immunology Case Registry and the Hepatitis C Case Registry with local and national databases. The CCR:HIV and CCR:HCV are administrative and clinical databases designed to provide population-based data on VA patients infected with Human Immunodeficiency Virus (HIV) and/or Hepatitis C virus (HCV). Each Veterans Health Information Systems and Technology Architecture (VistA) system contains a local CCR where patients who are potentially HIV or HCV infected are identified based on International Classification of Diseases (ICD-9) codes and/or positive antibody test results. The local HIV or HCV coordinator must review these cases to determine which patients are truly infected and should be added to the local registry. The local CCR provides extensive reporting capabilities to the local HIV and HCV clinicians to monitor their patient population. The local CCR software also extracts data elements from multiple VistA packages and transmits Health Level Seven (HL7) messages to the national database at VA Austin Information Technology Center. The national database is used for monitoring clinical outcomes, assessing resource utilization and quality assurance.