The VA National Clozapine Registry tracks the health and demographics of patients who have been prescribed clozapine by the VA. Clozapine, or the brand name Clozaril, is a drug used to treat the most serious cases of schizophrenia. Unfortunately, clozapine may also affect portions of the blood, lowering the body's resistance to infection and sometimes creating life-threatening circumstances. Realizing the severity of the problem, the Food and Drug Administration (FDA) established guidelines for analysis of White Blood Cells and Neutrophils and set strict minimum limits. The FDA also mandated that any manufacturer of clozapine must maintain a Clozapine Registry. These registries are to track the location and the health of clozapine patients and to ensure 'weekly White Blood Cell testing prior to delivery of the next week's supply of medication'. To date, the clozapine manufacturer registries have been unable to develop sufficient controls to meet these requirements, especially the ability to prevent dispensing clozapine when blood results are abnormal. However, because of the unique structure of Veterans Health Information Systems and Technology Architecture, the Veterans Health Administration obtained permission from the FDA and clozapine manufacturers to use its in-place computer network to gather and evaluate weekly patient information, then export this data to manufacturer clozapine registries. The VA assigned functional administration of this effort to the National Clozapine Coordinating Center (NCCC) located in Dallas, Texas. Weekly data on each VA clozapine patient is processed at two locations. Facility Level --When a clozapine prescription is written, a computer program in each facility's internal computer system retrieves white blood cell count, neutrophil count, and clozapine dose and evaluates the information according to FDA guidelines. If an adverse blood condition is found, the computer may warn to trigger a physician reevaluation, or lock out entirely to prevent dispensing, depending on the severity. Weekly, this information, along with certain patient demographic information, is gathered locally and transmitted to Hines Office of Information & Technology Field Office for centralized storage. This data can only be accessed by the NCCC. Raw data is downloaded from the Hines OI Field Office database on a weekly basis. An ancillary computer program reformats the data and evaluates the information for inconsistencies and data gathering errors. The computer-corrected data is manually compared with hand-written facsimile information sent to the NCCC by each site. This manually corrected data is again reformatted for data storage in MS Access format at the NCCC. The corrected data is also reformatted into American Standard Code for Information Interchange fixed-length fields and transmitted via modem to the manufacturers' Clozapine Registry and, in turn, to the FDA.