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Lead from Saliva

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Lead from Saliva Presented by Thomas McCormick, CEO Presentation compiled by Melissa Love and Shawn Maurer Original research conceived and developed by – PowerPoint PPT presentation

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Title: Lead from Saliva


1
Lead from Saliva
  • Presented by Thomas McCormick, CEO
  • Presentation compiled by Melissa Love and Shawn
    Maurer
  • Original research conceived and developed by
  • Dr. David Schneider, Chairman
  • Assistance in sample collection and testing by
    Patriot Drug Testing
  • Duane Fouts, R.Ph. and Erik Cissell
  • Western Slope Laboratory, LLC
  • and the North Carolina State Laboratory

2
Agenda
  • Present
  • It is well-known that ingested lead is toxic,
    especially to children
  • The current testing standard for lead uses whole
    blood
  • CDC recognized limits of quantification of the
    whole blood test are 10 µg/dL
  • Phlebotomists and special disposal infrastructure
    is necessary to test whole blood
  • Future
  • A test with a lower limit of quantification could
    help doctors and researchers better understand
    the effects of lead doses below 10 µg/dL on
    childrens development
  • A saliva test would not require phlebotomists and
    special disposal infrastructure and would be
    preferred by children
  • SolutionThe WSL Saliva Lead Test?
  • Preliminary studies of the WSL Saliva Lead Test
    indicate that it holds promise as a screen
  • Further studies may demonstrate a 11 correlation
    at doses above 10 µg/dL
  • Potentially the WSL Saliva Lead Test can be shown
    to be accurate below 10 µg/dL as well

3
Lead in the Body
  • Although death from lead poisoning is rare, lead
    has many toxic effects
  • Accumulation is gradual
  • Elevated blood pressure occurs at levels less
    than 10 µg/dL
  • This is the most common effect of lead toxicity
    in adults
  • It contributes to the hypertension epidemic
  • Headache, muscular weakness, and memory loss
    follow at higher doses
  • At doses higher than 40 µg/dL, kidney problems
    and infertility result 1

4
Lead Is Toxic for Children 1
  • Children are at greater risk for lead toxicity
    than adults
  • Childrens bodies absorb more ingested lead
  • Children put hands and other objects in their
    mouths more frequently
  • The fetal brain is especially at risk due to the
    immaturity of the blood-brain barrier
  • Lead interferes with normal neurodevelopment

5
Despite Risk Reduction, Threat Remains
  • Extensive media coverage has raised awareness 2
  • Risk has been greatly reduced over the last
    several decades via 1
  • Removal of tetraethyl lead from gasoline
  • Elimination of lead-solder from food cans
  • Removal of lead from plumbing and paint
  • Lead sources remain in the environment 3
  • Lead-based paint
  • Solder on pipes
  • Some foreign candies
  • Chinese toys
  • Hobbies such as making stained-glass windows
  • Occupational hazards

6
At-Risk Populations 4,5
  • Although legislation is in place to reduce
    exposure, approximately 310,000 US children ages
    one to five have blood levels above 10 µg/dL
  • About 1.5 of the population
  • Medicaid enrollees account for about 80 of US
    children ages one to five with whole blood lead
    levels greater than 20 µg/dL
  • Programs such as the Childhood Lead Poisoning
    Prevention Program (CLPPP) help many states test
    for lead
  • Some states require all Medicaid-enrolled
    children to be screened
  • If screened levels are higher than the 10 µg/dL
    cutoff, follow-up testing and treatment may be
    necessary

7
Neurodevelopmental Effects of Lead in Children
  • 2-4 point drop in IQ with each 1 µg/dL in the
    range of 5 35 µg/dL 1
  • Translates approximately to a 60 increase in
    developmentally disabled children and 40
    decrease in gifted children 2
  • There is evidence that the reduction in IQ is
    greatest per µg/dL when lead levels are below 10
    µg/dL 6
  • Children who have blood lead levels as low as 2
    µg/dL are four times as likely to be diagnosed
    with and treated for ADHD 7

8
Whole Blood is the Lead Test Standard
  • 95 of lead in blood is associated with the red
    blood cells 8
  • It is the found in hemoglobin and the cell
    membrane
  • The remainder is located in the blood plasma
  • To test, the cells are lysed, and lead content is
    measured by a CDC approved method
  • Graphite-furnace atomic absorption spectroscopy
    (7105) 9
  • ICP-MS (7300) 10
  • Capillary blood is used for screens venous
    blood is considered the definitive test
  • Current CDC approved lead whole blood tests are
    only considered accurate at levels more than 10
    µg/dL
  • According to the CDCs website, children cannot
    be accurately classified as having blood lead
    levels above or below a value less than 10 µg/dL
    because of the inaccuracy inherent in laboratory
    testing. 11
  • In children, a whole blood lead level of 10 µg/dL
    is the CDC-recognized level of action

9
Other Methods of Lead Testing
  • If an alternative lead test was deemed as
    accurate as a whole blood test above 10 µg/dL and
    also accurately measures body lead below 10
    µg/dL, then researchers would be able to
    determine what effects, if any, lower doses of
    lead have
  • This could lead to a lowering of the current
    level of action for children

10
Promising Saliva Lead Testing Studies
  • Lead in saliva correlates more with lead levels
    in blood plasma than with levels in blood 12
  • Gonzalez et al. 1997 suggest that saliva is a
    good lead monitoring medium as their measured
    levels correlated to recent exposure in Mexico
    City 14
  • Timchalk et al. at Pacific Northwest Laboratory
    showed in 2006 that there is a strong correlation
    in lead in saliva vs. plasma (r20.922) in lead
    acetate dosed rats 8
  • Koh and Koh, 2007, state that blood contamination
    of saliva may prove to be a potential problem,
    but that saliva could be used to monitor lead in
    higher levels of exposure (gt50 µg/dl) 15

11
Less Promising Saliva Lead Testing Studies
  • Barbosa et al. in 2006 showed poor correlations
    between lead in saliva vs. blood (r0.277,
    P0.008) and lead in saliva vs. plasma (r0.280,
    P0.006) 16
  • Age and gender did not affect lead saliva levels
    or the lead-saliva/lead-plasma ratio
  • Collected only parotid saliva
  • Wilhelm et al. in 2002 showed that saliva is not
    a good medium for measuring lead in children 17
  • Collected saliva with no stimulation
  • No reference materials were available
  • Lead saliva tests have had trouble with
    consistency

12
The WSL Saliva Lead Test
  • The WSL Saliva Lead Test uses citric acid to
    induce serous salivation, allowing for a
    consistent measurement
  • Filter paper strips are dosed with citric acid
    via soaking in super-saturated lemonade mix
  • Sample collection consists of the donor holding
    the filter in their mouths until it is soaked
    through
  • It is then placed in an air-tight container until
    analysis can be performed
  • Highly trained personnel are not necessary for
    sample collection
  • The filter paper strips, which hold a known
    volume of saliva, are digested in 20 HNO3
  • The resulting solution is filtered and run on
    ICP-MS
  • ICP-MS has a detection limit less than 0.1 ppb
    for lead, whereas GFAAS has a detection limit of
    2 ppb 6,9
  • ICP-MS also has a low chance of interference

13
The North Carolina Study
  • People who came in for mandatory lead testing and
    nutritional screening in Guilford County, NC in
    October 2005 gave venous whole blood and saliva
    samples at the same time
  • Collectors from Patriot Drug Testing gathered the
    saliva samples
  • Lead analysis from venous whole blood was
    performed by the North Carolina State Lab
  • Lead from saliva was measured by Western Slope
    Lab employees on PE Elan DRCe ICP-MP at a Perkin
    Elmer laboratory in Chicago, IL
  • Filter paper strips were digested in 20 HNO3 in
    a Hot Block Digestion Bath

14
Results from the North Carolina Study
  • We know from an F-test that the sample variances
    are the same
  • Hence, we may use a t-test to investigate the
    null hypothesis
  • We find that the means are the same within 97.5
    confidence interval for a two-tail distribution
  • All samples in the study had values measured by
    both WSL and the NC State Laboratory as less than
    10 µg/dL
  • Given that the venous blood test is not
    considered accurate at such lead levels, the
    results are promising

15
Further Studies Are Required
  • The data do not include samples that were
    measured as being above 10 µg/dL by WSL or the NC
    State Laboratory
  • In order to demonstrate the agreement of whole
    blood and WSL Lead Saliva tests, samples above 10
    µg/dL must be measured with both methods
  • The difference in lead levels between the paired
    samples is in all cases less than 4 µg/dL
  • If the variance at higher lead levels is the same
    as at the low lead levels measured, then the WSL
    saliva test holds promise for good agreement with
    whole blood tests
  • More results may indicate that whole blood and
    the WSL saliva method show 11 correlation at
    concentrations above 10 µg/dL

16
Acknowledgements
  • The Centers for Disease Control and Prevention
  • The children and families who participated in the
    North Carolina Study
  • The North Carolina State Laboratory
  • Duane Fouts, R.Ph., Erik Cissell, and all others
    who helped in sample collection and analysis
  • Perkin-Elmer

17
References
  • Curtis D Klaasssen, ed. Casarett and Doulls
    Toxicology The Basic Science of Poisons. 5th
    ed. New York McGraw-Hill, 1996.
  • Jonathon Sher. Ontario lead laws faulted. The
    London Free Press June 5, 2007, final ed B1.
  • Lead poisioning. nsc.org . 14 Aug 2008.
    National Safety Council. 14 Aug 2008
    http//www.nsc.org/resources/issues/lead.aspx.
  • Alan B. Bloch, Lisa R. Rosenblum, Anne M.
    Guthrie. Recommendations for Blood Lead
    Screening of Young Children Enrolled in Medicaid
    Targeting a Group at High Risk. MMWR. 8 Dec,
    2000. CDC. 14 Aug 2008 http//www.cdc.gov/mmwR/p
    review/mmwrhtml/rr4914a1.htm.
  • General Lead Information Questions and
    Answers. NCEH. 14 Aug 2008. CDC. 14 Aug 2008
    http//www.cdc.gov/nceh/lead/faq/about.htm.
  • Matthew M. Matusiak. Analysis of lead in whole
    blood using the Thermo Electron X Series ICP-MS.
    The Internet Journal of Laboratory Medicine.
    2006 Volume 1, Number 2. 7 Aug 2008
    http//www.ispub.com/ostia/index.php?xmlFilePathj
    ournals/ijlm/vol1n2/lead.xml.
  • Joe M. Braun, Robert S. Kahn, Tanya Froehlich,
    Peggy Auinger, and Bruce P. Lanphear. Exposures
    to Environmental Toxicants and Attention Deficit
    Hyperactivity Disorder in US Children.
    Environmental Health Perspectives. V 114 No 12
    (2008) 1904-09.
  • C. Timchalk, Y. Lin, K.K. Weitz, H. Wu, R.A.
    Gies, D.A. Moore, W. Yantasee. Disposition of
    Lead (Pb) in salica and blood of Sprague-Dawley
    rats following a single or repeated oral exposure
    to Pb-acetate. Toxicology. 222 (2006) 86-94.
  • Schlecht, P.C. O'Connor, P.F. Eds. LEAD by
    GFAAS. NIOSH Manual of Analytical Methods, 4th
    ed. 1994 7105. 10 Aug 2008. http//www.cdc.gov/
    niosh/nmam/pdfs/7105.pdf.
  • Schlecht, P.C. O'Connor, P.F. Eds. ELEMENTS by
    ICP. NIOSH Manual of Analytical Methods, 4th
    ed. 1994 7300. 10 Aug 2008. http//www.cdc.gov/
    niosh/nmam/pdfs/7300.pdf.
  • Why not change the blood lead level of concern
    at this time? NCEH. 14 Aug 2008. CDC. 14 Aug
    2008 http//www.cdc.gov/nceh/lead/faq/changeBLL.ht
    m.
  • Fernando Barboa Jr., José Eduardo Tanus-Samtps.
    Raquel Fernanda Gerlack, Patrick J. Parsons. A
    Criticial Review of Biomarkers Used for Monitorin
    Human Exposure to Lead Advantages, Limitations,
    and Future Needs. Environmental Health
    Perspectives. V 13 No 12 (2005) 1669-74
  • Ingvar A. Bergdahl, Lars Gerhardsson, Ingrid E.
    Liljelind, Leif Milsson, Staffan Skerfving.
    Plasma-Lead Concentration Investigations into
    its Usefulness for Biological Monitoring of
    Occupatoinal Lead Exposure. American Journal of
    Industrial Medicine. 49 (2006) 93-101
  • M. Gonzalez, J.A. banderas, A. Baez, R. Belmont.
    Salivary lead and cadmium in a young population
    residing in Mexico city. Toxicology Letters.
    93 (1997) 55-64
  • David Soo-Quee Koh, Gerald Choon-Huat Koh. The
    use of salivary biomarkers in occupational and
    environmental medicine. Occupational
    Environmental Medicine. 64 (2007) 202-210
  • Fernando Barbosa Jr., Maria Heloísa Corrêa
    Rodrigues, Maria R. Buzalaf, Francisco J. Krug,
    Raquel F. Gerlach, José Eduardo Tanus-Santos.
    Evaluation of the use of salivary lead levels as
    a surrogate of blood lead or plasma lead levels
    in lead exposed subjects. Archives of
    Toxicology. 80 (2006) 633-637
  • M. Wilhelm, A. Pesch, U. Rostek, J. Beberow, N.
    Schmitz, H. Idel, U. Ranft. Concentrations of
    lead in blood, hair and saliva of German children
    living in three different areas of traffic
    density. TheScience of the Total Environment.
    297 (2002) 109-118

18
Western Slope Laboratory, LLC
  • Founded in 2002 by Chairman Dr. David Schneider,
    Ph.D.
  • Pharmacologist
  • Assoc. Prof. Pharmacology, Wayne State
    University School of Medicine, Detroit, MI
  • Became 1st wholly-owned subsidiary of Coventry
    Diagnostics, LLC after re-structuring
  • Located in Troy, MI
  • WSL primarily tests for drugs of abuse, alcohol
    metabolites and steroids in saliva and/or urine

19
Coventry Diagnostics, LLC
  • Coventry is a research company focused on
    discovering and developing novel solutions using
    saliva-based diagnostics
  • Coventry has many ongoing research investigations
  • Metabolism of cancer agents for molecular biology
    studies, clinical trials, and dosing purposes
  • Metabolism and dosing of delirium and
    antipsychotics
  • Genetics, metabolism, and dosing of warfarin
  • Testing for lead and other heavy metals
  • Coventry spins off production companies such as
    Western Slope Laboratory, LLC

20
  • Where Applied and Pure
  • Research
  • Becomes Reality
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