Integrating the New York citywide immunization registry and the childhood blood lead registry.

In February of 2004- the New York City Department of Health and Mental Hygiene completed the integration of its childhood immunization and blood lead test registry databases- each containing over 2 million children. A modular approach was used to build a separate integrated system- called Master Child Index- to include all children in both the immunization and lead test registries. The principal challenge of this integration was to properly align records so that a child represented in one database is matched with the same child in the other database. To accomplish this task as well as to identify internal duplicate records within each database- an artificial intelligence record linkage system was created. The preliminary results show high rates of accurate merging of records both within and between the two databases. The 4-610-585 records contained in both databases before Master Child Index implementation consolidated into 2-977-290 records in the integrated system. The matching system eliminated 523-720 dup