A simple blood lead test can be done to detect the level of lead in your body. This is usually performed on a sample drawn from a vein in the arm but may sometimes be performed on a sample from a fingerstick. If the fingerstick sample is abnormal, then it is frequently followed by a sample taken from the arm to confirm the findings. Blood lead levels are a snapshot of the amount of lead in the blood at that moment. They are the best test for detecting and evaluating recent acute and chronic exposure. Blood lead samples are used to screen for exposure and to monitor the effectiveness of treatment.

The zinc protoporphyrin (ZPP) test is an old test that has fallen out of favor with many physicians for screening. The ZPP test result increases because lead interferes with the red blood cells' ability to make hemoglobin. It serves as an average of lead exposure over time and is not affected by the location of lead in the body. The ZPP will not reflect recent exposure to lead; it falls more slowly than lead levels once the person is removed from the source of lead exposure, and it does not usually become abnormal until the lead concentration is greater than 25 micrograms per deciliter. This means it is not sensitive enough to be useful as a screening test for children (where the goal is a lead level below 10 micrograms per deciliter). The ZPP test result will also be elevated due to inflammation, so the test is not considered a definitive marker of lead exposure.

In 1997, the Centers for Disease Control and Prevention (CDC) issued revised screening guidelines for blood lead in children. The CDC guidelines define testing intervals and actions for children with elevated blood lead levels.

In 2002, the CDC issued additional guidelines (http://www.cdc.gov/nceh/lead/CaseManagement/caseManage_main.htm) that offered recommendations for managing and monitoring those children whose blood levels were found to be elevated.

When elevated lead levels are present in children (greater than about 20 micrograms per deciliter), then the doctor may order a hemoglobin and/or hematocrit test to determine if the patient is anemic, and may order iron tests to evaluate whether or not the patient is iron deficient.