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Test Code PBZP Lead Profile Occupational Exposure, Blood

Useful For

Detecting lead toxicity

Profile Information

Test ID Reporting Name Available Separately Always Performed
PBB Lead, B Yes, (order PBDB) Yes
ZPPB Zinc Protoporphyrin, B Yes, (order NEZPP) Yes
DEMO5 Patient Demographics No Yes

Method Name

PBB: Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)

ZPPB: Hematofluorometry

Reporting Name

Lead Profile Occ Exposure, B

Specimen Type

Whole blood


Specimen Required


Patient Preparation:

High concentrations of gadolinium and iodine are known to interfere with most metals tests. If either gadolinium- or iodine-containing contrast media has been administered, a specimen should not be collected for 96 hours.

Supplies:

Metal Free B-D Tube (EDTA), 6 mL (T183)

Metal Free (Lead only) EDTA Tube, 3 mL (T615)

Microtainer (EDTA) Tube, 0.5 mL (T174)

If ordering the EDTA trace element Vacutainer tube from BD, order catalog #368381

Container/Tube:

Preferred: Royal blue-top BD Vacutainer Plus with EDTA blood collection tube (T183)

Acceptable: Tan-top (lead only) BD Vacutainer Plus with EDTA blood collection tube (T615) or BD Microtainer with EDTA (T174) or royal blue-top Monoject trace element blood collection tube

Specimen Volume: 2 mL

Collection Instructions:

1. See Trace Metals Analysis Specimen Collection and Transport in Special Instructions for complete instructions.

2. Send specimen in original tube.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Whole blood Refrigerated 28 days

Reject Due To

Hemolysis

Mild reject; Gross reject

Lipemia

Mild reject; Gross reject

Icterus

NA

Other

Clotted specimen, Green top heparin tube

Clinical Information

Lead is a heavy metal commonly found in man's environment that can be an acute and chronic toxin.

 

Lead was banned from household paints in 1978, but is still found in paint produced for nondomestic use and in artistic pigments. Ceramic products available from noncommercial suppliers (such as local artists) often contain significant amounts of lead that can be leached from the ceramic by weak acids such as vinegar and fruit juices. Lead is found in dirt from areas adjacent to homes painted with lead-based paints and highways where lead accumulates from use of leaded gasoline. Use of leaded gasoline has diminished significantly since the introduction of nonleaded gasolines that have been required in personal automobiles since 1972. Lead is found in soil near abandoned industrial sites where lead may have been used. Water transported through lead or lead-soldered pipe will contain some lead with higher concentrations found in water that is weakly acidic. Some foods (for example: moonshine distilled in lead pipes) and some traditional home medicines contain lead.

 

Lead expresses its toxicity by several mechanisms. It avidly inhibits aminolevulinic acid dehydratase (ALA-D) and ferrochelatase, 2 of the enzymes that catalyze synthesis of heme; the end result is decreased hemoglobin synthesis resulting in anemia.

 

Lead also is an electrophile that avidly forms covalent bonds with the sulfhydryl group of cysteine in proteins. Thus, proteins in all tissues exposed to lead will have lead bound to them. The most common sites affected are epithelial cells of the gastrointestinal tract and epithelial cells of the proximal tubule of the kidney.

 

The typical diet in the United States contributes 1 to 3 mcg of lead per day, of which 1% to 10% is absorbed; children may absorb as much as 50% of the dietary intake, and the fraction of lead absorbed is enhanced by nutritional deficiency. The majority of the daily intake is excreted in the stool after direct passage through the gastrointestinal tract. While a significant fraction of the absorbed lead is rapidly incorporated into bone and erythrocytes, lead ultimately distributes among all tissues, with lipid-dense tissues such as the central nervous system being particularly sensitive to organic forms of lead. All absorbed lead is ultimately excreted in the bile or urine. Soft-tissue turnover of lead occurs within approximately 120 days.

 

Avoidance of exposure to lead is the treatment of choice. However, chelation therapy is available to treat severe disease. Oral dimercaprol may be used in the outpatient setting except in the most severe cases.

 

Erythrocyte protoporphyrin is a biologic marker of lead toxicity. Lead inhibits several enzymes in the heme synthesis pathway and causes increased levels of RBC zinc protoporphyrin (ZPP).

Reference Values

LEAD

All ages: 0.0-4.9 mcg/dL

Critical values

Pediatrics (≤15 years): ≥20.0 mcg/dL

Adults (≥16 years): ≥70.0 mcg/dL

 

ZINC PROTOPORPHYRIN

<100 mcg/dL

All measurements assume hematocrit of 42% and are made in mcg/dL per OSHA requirements.

Interpretation

The Centers for Disease Control and Prevention (CDC) has identified the blood lead test as the preferred test for detecting lead exposure in children. Chronic whole blood lead levels below 10 mcg/dL are often seen in children. For pediatric patients, there may be an association with blood lead values of 5 to 9 mcg/dL and adverse health effects. Follow-up testing in 3 to 6 months may be warranted. Chelation therapy is indicated when whole blood lead concentration is above 25 mcg/dL in children or above 45 mcg/dL in adults.

 

The Occupational Safety and Health Administration (OSHA) has published the following standards for employees working in industry:

-Employees with whole blood lead levels above 60 mcg/dL must be removed from workplace exposure.

-Employees with whole blood lead levels above 50 mcg/dL averaged over 3 blood samplings must be removed from workplace exposure.

-An employee may not return to work in a lead exposure environment until their whole blood lead level is below 40 mcg/dL.

-All measurements assume hematocrit of 42% and are made in mcg/dL per OSHA requirements.

 

Elevated zinc protoporphyrin (ZPP) levels in adults may indicate long-term (chronic) lead exposure or may be indicative of iron deficiency anemia or anemia of chronic disease.

Clinical Reference

1. National Report on Human Exposure to Environmental Chemicals. Centers for Disease Control and Prevention. Updated Feb 2015. Available at http://www.cdc.gov/exposurereport

2. Occupational Safety and Health Administration: OSHA Lead Standard-Requirements from the General Industry Standards Lead (1910, 1025), from 29 CFR 1910, 1025, A.M. Best Safety and Security-2000. Retrieved July 2016. Available at  https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10033

3. de Burbure C, Buchet J-P, Leroyer A, et al: Renal and neurologic effects of cadmium, lead, mercury, and arsenic in children: evidence of early effects and multiple interactions at environmental exposure levels. Environ Health Perspect 2006;114:584-590

4. Kosnett MJ, Wedeen RP, Rothenberg SJ, et al: Recommendations for medical management of adult lead exposure. Environ Health Perspect 2007;115:463-471

5. Jusko T, Henderson C, Lanphear B, et al: Blood lead concentrations <10 mcg/dL and child intelligence at 6 years of age. Environ Health Perspect 2008;116:243-248

Day(s) and Time(s) Performed

Monday through Friday; 5 pm

Analytic Time

1 day

Performing Laboratory

Mayo Medical Laboratories in Rochester

CPT Code Information

83655-Lead

84202-Protoporphyrin, RBC; Quantitative

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PBZP Lead Profile Occ Exposure, B In Process

 

Result ID Test Result Name Result LOINC Value
42389 Zinc Protoporphyrin, B 33007-6
VECP Venous/Capillary 31208-2
8602 Lead, B 77307-7
PTADD Patient Street Address 56799-0
PTCIT Patient City 68997-6
PTSTA Patient State 46499-0
PTZIP Patient Zip Code 45401-7
PTCNT Patient County 87721-7
PTPHO Patient Home Phone 42077-8
PTRAC Patient Race 32624-9
PTETH Patient Ethnicity 69490-1
PTOCC Patient Occupation 11341-5
PTEMP Patient Employer 80427-8
GDFN Guardian First Name 79183-0
GDLN Guardian Last Name 79184-8
MDORD Health Care Provider Name 52526-1
MDADD Health Care Provider Street Address 74221-3
MDCIT Health Care Provider City 52531-1
MDSTA Health Care Provider State 52532-9
MDZIP Health Care Provider Zip Code 87702-9
MDPHO Health Care Provider Phone 68340-9
LABPH Submitting Laboratory Phone 65651-2

Test Classification

See Individual Test IDs

Secondary ID

42390

Forms

Lead/Heavy Metals Reporting Form (T491) in Special Instructions