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Lab Manual for UCSF Clinical Laboratories

Lab Manual for SFGH

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LEAD, BLOOD

Item Value
Available Stat? No
Test code BPB
Performed by? Chemistry
Sendout? no
Price range $$$
In House Availability Performed 3 times/week
Principle Anodic Stripping Voltammetry
Interpretation A free erythrocyte protoporphyrin evaluation should be made if considering the differential diagnosis of signs or symptoms caused by lead. If considering the possibility of excessive exposure but without clinical symptoms, free erythrocyte protoporphyrin will not be useful. In pediatric populations, lead concentrations greater than 10 mcg/dL indicate excessive exposure to environmental lead. In adult populations, working near lead contaminated areas, blood lead concentrations greater than 40 mcg/dL of whole blood are considered as evidence of harmful exposure.
Patient Preparation CONDITIONS FOR PREPARATION OF PATIENT AND SPECIMEN:

1. Patient should refrain from eating seafood, antacids, vitamins with mineral supplements, and herbal preparations at least 3 days before collection of specimen.

2. Before drawing blood, the draw site should be cleaned by washing with soap and water. This is especially important for a capillary blood draw. ALLOW SITE TO AIR DRY, DO NOT dry with paper towels

3. All jewelry, including watches, should be removed, and hands washed prior to putting on gloves and drawing sample.

4. Disinfect the site with isopropyl alcohol.

5. If drawing multiple tubes, the blood lead sample should be drawn last.

6. Mix tubes well to avoid clot formation.

7. Avoid other items that can cause lead contamination, including dust, keys or key rings, cellphones, sunglasses, and other items that children play with or chew on.

Container type EDTA tan or pediatric lavendar top tube
Regular EDTA tubes are not approved for this test.
Amount to Collect 3 mL
Normal range < 5 µg/dL

Source of reference ranges:

The Fourth National Report on Human Exposure to Environmental Chemicals, Updated Tables, September 2012, Department of Health and Human Services (based on NHANES 2009- 2010
)
California Management Guidelines on Childhood Lead Poisoning for Health Care Providers http://www.cdph.ca.gov/programs/CLPPB/Pages/ScreenRegs-CLPPB.aspx

For OSHA guidelines on monitoring lead levels in the workplace and for information on lead levels that require removal of an employee from work (workplace exposure to lead), see http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=standards&p_id=10030
Stability 1 week at 2-8°C or 1 month at -20°C.
Additional information For treatment guidelines in children based on blood lead levels, click here: http://www.cdph.ca.gov/programs/CLPPB/Pages/ScreenRegs-CLPPB.aspx

For treatment guidelines in adults based on blood lead levels, see: www.uptodate.com

This test method is NOT suitable for patients receiving treatment with Succimer [DMSA] or D-Penicillamine; contact the laboratory to arrange testing by an alternate method [AAS].

To convert µg/dL to µmol/L (SI units) multiply by 0.0483.

Capillary specimens for lead are easily contaminated. Capillary specimens are acceptable for screening but all retests on BLLs ≥ 10 mcg/dL should be on venous blood. When a reference is made to a "venous" specimen, arterial or umbilical line specimens may be substituted. Use of a heelstick instead of a fingerstick to obtain a capillary specimen is recommended in children under one year of age.

Consider retesting in six months, particularly if the BLL is approaching 10 mcg/dL and the child is less than two years of age, is at high risk for lead exposure, or was tested at the start of warm weather (when BLLs tend to increase).

Initiation of chelation therapy:

Adults:
According to UpToDate (www.uptodate.com), "chelation in adults should generally be initiated for individuals with blood lead levels greater than 100 mcg/dL (4.83 micromol/L), and should also be considered for levels between 80 to 100 mcg/dL in asymptomatic individuals and for blood lead levels between 50 to 80 mcg/dL (2.41 to 3.86 micromol/L) in individuals with lead-related symptoms. In addition, chelation is sometimes considered in persons with even lower blood lead levels [eg, ≥ 40 mcg/dL (1.93 micromol/L)] if they have continued symptoms and elevated blood lead levels after two weeks of removal from exposure. Two chelating agents most commonly used to treat adults are DMSA and CaEDTA. Chelation with any agent should not be undertaken unless exposure has been definitively curtailed, since its use in the presence of continuing exposure may result in enhanced absorption of lead and worsening, rather than amelioration of toxicity. "

Children: see California Management Guidelines on Childhood Lead Poisoning for Health Care Providers: http://www.cdph.ca.gov/programs/CLPPB/Pages/ScreenRegs-CLPPB.aspx

All blood lead results are electronically sent to the California Department of Health Services weekly.

In addition, all blood lead results on patients less than 18 years of age who reside in the City and County of San Francisco, California are faxed weekly to the San Francisco City and County Department of Public Health - Childhood Lead Poisoning Program.


References 1. Tietz NW (ed). Fundamentals of Clinical Chemistry. Ed. 5. Philadelphia: WB Saunders, 377-378, 2001.

2. Center for Disease Control, Preventing Lead Poisoning in Young Children, October, 1991.

3. NCCLS. Analytical Procedures for the Determination of Lead in Blood and Urine; Approved Guideline. NCCLS document C40-A. NCCLS, Wayne, PA. 2001.

4. Operating Manual: Model 3010B Lead Analyzer, part # 70-1059 Rev F, ESA, Inc., Chelmsford, MA, 1993.

5. California Childhood Lead Poisoning Prevention Branch website: http://www.dhs.ca.gov/childlead/.

6. Centers for Disease Control Childhood Lead Poisoning Prevention Program website: http://www.cdc.gov/nceh/lead/lead.htm

7. American Academy of Pediatrics, Screening for Elevated Blood Lead Levels website: http://aappolicy.aappublications.org/cgi/content/full/pediatrics%3b101/6/1072

8. San Francisco Department of Public Health, Maternal and Child Health, Healthy Outlook, Winter 2004. Lead testing training for CHDP Providers. http://www.dph.sf.ca.us/PHP/CHDPNewsltrs/MCHWinterNewsltr2004.pdf
CPT coding 83655
Last Updated 9/16/2015 5:01:56 PM
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