Course Content Page 6

Blood Lead Testing

When a blood test for lead is indicated, venipuncture-collected (venous) blood samples provide the most reliable results. Using the venipuncture method, the chance of contamination from environmental factors or the patient's hand/fingers decreases. Note that blood lead analysis may be performed through capillary sampling. However, these results are susceptible to lead contamination on the skin. Proper preparation of the capillary collection site is essential to obtain a meaningful blood lead level. Any capillary collection with elevated results should be confirmed using venipuncture collection.

Erythrocyte protoporphyrin (EP, ZPP) test is not recommended as a blood lead-screening tool. This test reflects the status of heme synthesis and is not sensitive to detect lead levels less than 25 µg/dl (14). Current laboratory testing for lead in blood is done more accurately using atomic absorption. In this method, the lead is vaporized and light of a very specific wavelength is conducted through the vapor. If lead is present, the light is partially extinguished.

Prenatal Testing

Pregnant women at risk for lead poisoning should have their blood lead level tested using venous collection methods. Testing can be done at the physician's office or at the local health agency. Should a woman object to being tested, a written statement that identifies the reason for refusing the testing should be obtained. The refusal statement should include the woman's name, date of birth, reason for refusal and date of refusal, and should become part of the woman's medical record.

Continue to Course Content Page 7...