Using state lead poisoning surveillance system data to assess false positive results of capillary testing.

Objective: The purpose of this study was to determine the false positive percentage of capillary blood lead screening in a statewide surveillance system and to explore potential predictors of false positive results.

Methods: Data were all blood lead tests of 0-5 year old children in Maine during 2002-2003. We determined the proportion of children with elevated (>/=10 microg/dL) capillary test results who received a venous confirmatory test, and calculated the percentage of false positive tests, defined as a capillary test of >/=10 microg/dL with a confirmatory venous test of <10 microg/dL.