Title: Lead from Saliva
1Lead 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
2Agenda
- 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
3Lead 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
4Lead 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
5Despite 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
6At-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
7Neurodevelopmental 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
8Whole 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
9Other 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
10Promising 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
11Less 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
12The 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
13The 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
14Results 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
15Further 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
16Acknowledgements
- 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
17References
- 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
18Western 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
19Coventry 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