It is essential for children suffering from or at risk of lead poisoning to have regular follow-up, and specifically for their blood lead (Pb) levels to be monitored. The present study assessed the occurrence of late follow-up testing of blood lead levels in children in Greater Paris, and factors related to such delays.
Since 1992, the SSSIILF has been systematically recording data on lead levels in blood tests conducted for screening and follow-up in Greater Paris. For Pb greater or equal to 45 microg/dL (Group 4), a further blood lead test has to be done within three weeks. For levels of 25 microg/dL < or = Pb < 45 microg/dL (Group 3) and 10 microg/dL < or = Pb < 25 microg/dL (Group 2), a second test must be done within 6 months. For Pb less than 10 microg/dL combined with one or more risk factors (Group 1: children at risk of poisoning), a second test is required within 6 to 12 months. Children aged 1 to 6 years who were screened between 1992 and 2002 were selected. The occurrence of late follow-up testing was estimated, and the independent effect of each variable associated with a delay was measured using a logistic regression model.
Delays in re-testing were reported for 66.9% of Group 4 children (n=356), 45.3% of Group 3 children (n=921), 74.1% of Group 2 children (n=5,466), and 88.7% of Group 1 children (n=15,612). In the three groups with Pb greater or equal to 10 microg/dL, there was better follow-up (i.e. less delay to re-testing) for children screened most recently, those whose initial blood lead test results were elevated, those who lived in sub-standard housing built before 1949, and those who lived in suburban districts of Paris. The delay was longer for children aged 4 to 6 compared to younger children. When the size of the group was large enough, these differences were significant. In Group 1, similar results were observed except for a home address in a suburban district. Furthermore, follow-up was better for children of Sub-Saharan African parents, children whose initial prescription had been issued by a "PMI" mother/child healthcare centre and children from large families.
Despite substantial delays in carrying out follow-up blood lead level testing, these delays were shorter for the populations with the greatest exposure.