Clinical Chemistry - Blood Lead
- Policy Memo Regarding CDC Recommendations: Revised Follow-Up Schedule for Blood Lead Testing
- Follow-Up Schedule for Diagnostic / Confirmed Blood Lead Levels (PDF, 45 KB) - Each block in the table represents a risk category. Each blood lead test performed must be confirmed within that category. If the diagnostic blood lead test moves to a higher risk category, then confirmation must be done in the higher risk-category. Additional information can be found in the Childhood Lead Testing and Follow-Up Manual from the NC Department of Environment and Natural Resources.
Childhood lead poisoning is a major, preventable environmental health problem. The persistence of lead poisoning, in light of present knowledge about the sources, pathways and prevention of lead exposure, continues to present a direct challenge to clinicians and public health authorities. As a result of industrialization, lead is common in the environment. Lead has no known physiological value and children are particularly susceptible to its toxic effects. Most poisoned children have no apparent symptoms, and consequently, many cases go undiagnosed and untreated. Lead poisoning is widespread and is not solely a problem of inner city or minority children. No socioeconomic group, geographic area, racial or ethnic population is spared its effects.
Blood lead testing is encouraged as an important element of a comprehensive program to eliminate childhood lead poisoning. The goal of such testing is to identify children who need individual interventions to reduce their exposure.
New data indicate adverse effects of lead exposure in children at blood lead levels previously believed to be safe. Blood lead levels as low as 5 micrograms per deciliter (mg/dL) are associated with harmful effects on children's learning and behavior. At higher levels (³70 mg/dL), lead exposure is an acute condition and can have devastating health consequences, including encephalopathy, seizures, coma and even death. As a result, the Centers for Disease Control (CDC) 1993 intervention level of 10ug/dL has been lowered to 5 ug/dL.
Direct blood lead measurement is the initial screening test of choice. In addition, a multi-tier approach to follow-up has been adopted with an overall goal of reducing children’s blood lead levels to below 5 ug/dL, effective July 2012.
Who and When to Screen
All children seen at local health departments for health maintenance visits (Well Child and Well Baby Clinics; Early Periodic Screening Diagnosis Treatment (EPSDT) clinics; Pediatric Supervisory Clinics; WIC Children, etc) and all children receiving services through private providers are to be screened at least once before the age of six without regard to risk determination.
Ideally, children should be tested between 12 and 24 months of age, or upon their first entry to the health care system at a later age. Children identified as high risk should be rescreened in 12 months.
The screening specimen should be collected by the child’s primary care provider. Referral to a provider solely for the purpose of lead screening is discouraged.
Screening Test and Methodology
Direct blood lead measurement is the screening test of choice. Finger-stick, capillary blood specimens are adequate for the initial screening test, provided that precautions are taken to minimize the risk of contamination. Venous blood specimens should be collected for confirmation of all elevated blood lead results.
The State Laboratory is available to analyze blood specimens collected by local health departments and blood specimens on all children 6 months - 6 years of age who are seen by private providers.
Specimen Identification, Collection and Shipment
B. Complete all identification and requested information on DHHS form #3707. It is imperative that all of the following information be completed:
- Patient last name, first name, middle initial
- Date of birth
- Race and sex
- Medicaid number
- Submitter name, address and tax identification number (EIN#)
- Specimen collection date
- Indicate whether Initial or follow-up blood lead test
Submit an EDTA (lavender top) microtainer or venous blood specimen (full, unopened tube) labeled with patient’s name and date of birth. Laboratory testing will NOT be performed unless the information on the specimen tube exactly matches information on the collection form.
C. Preparation of Child
- Wash child’s hand with soap and water, using hand brush. Rinse well. Dry.
- Grasp the child’s hand so that the blood drawer’s thumb is across the top of the child’s fingers.
- Hold the child’s hand so that the palm faces up.
- Use child’s middle or ring finger for sample collection.
- Using an alcohol wipe, briskly scrub area on the child’s fingertip for 20 seconds.
- Wipe scrubbed area once, using dry gauze.
- Use lancet to stick finger slightly left of center.
- Use dry gauze to wipe off the first drop of blood.
Note: After specimen collection, care of puncture site should be consistent with your institution’s procedures.
D. Collection of Blood Sample
- Continuing to grasp the finger, touch the capillary tip of the collection device to the beaded drop of blood.
- Capillary must be held continuously in a horizontal position during specimen collection to prevent air bubbles from forming in the capillary tube.
- Dispense the full capillary of blood (200 – 250 μL) into the microtainer.
- Turn capillary/tube unit immediately to a vertical position to allow the blood in the capillary to flow into the tube.
- Remove capillary with holder at the same time. Close microtainer with attached cap.
- Agitate the specimen to mix the anticoagulant through the blood.
- Label microtainer with patient’s first and last name and date of birth and refrigerate until shipping.
*Laboratory testing will NOT be performed unless the information on the specimen tube exactly matches information on the collection form.
- The Laboratory must receive the specimen within 28 days of collection; however, immediate shipping is recommended to ensure specimen integrity and suitability for analysis.
- If not shipped immediately, store in refrigerator.
Reporting Procedures and Interpretation
Children are classified according to the risk for adverse effects of lead based solely on blood lead measurement. The urgency and type of follow-up required are based on a child’s risk classification.