Filter Paper Testing
The California Department of Public Health Childhood Lead Poisoning Prevention Branch (CLPPB) adheres to guidance from the Centers for Disease Control and Prevention (CDC) regarding filter paper testing. Filter paper testing has multiple issues of possible contamination that are well documentedā.(PDF)
The policy statemenāāt below provides guidance for discontinuing the use of filter paper testing and information on retesting children who have had filter paper lead screening or testing in the past. The test methodology that is recommended depends on the initial blood lead value, whether less than the CDC Blood Lead Reference Value (BLRV) of 3.5 mcg/dL, or equal to or greater than the CDC BLRV of 3.5 mcg/dL.
CLPPB Filter Paper Testing Policy:
If you are currently using filter paper testing for blood lead tests, please discontinue its use. If you have used filter paper in the past to test children under the age of six, and the test result was less than 3.5 mcg/dL, the test should be repeated with another screening using EITHER capillary blood and an FDA-approved Point of Care testing device OR capillary or venous blood sent to a lab. If the filter paper result was equal to or greater than 3.5 mcg/dL, repeat with a venous test and send the blood sample for analysis to a reference lab that runs inductively coupled plasma mass spectrometry (ICP-MS) or graphite furnace atomic absorption spectrometry (GFAAS).