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Section 7
Observer Comments
On both days of the panel discussions, observers were given the opportunity to provide input on issues related to the charge questions and panel deliberations. Observer comments received during the meeting are summarized below, alphabetized by observer's name. A full list of observers and their respective positions and affiliations is included in Appendix F. Observers were asked to provide appropriate references and data to support their statements where possible. Statements provided without reference are included, but have not been verified or validated by ATSDR or the panel. In some cases panelists responded to a particular observer comment or question; such responses are summarized in this section as well.
Observers were also encouraged to provide written comments after the June 12–13, 2001, panel discussions. Appendix G includes written comments from two individuals.
Erik Auf der Heide
ATSDR
Dr. Auf der Heide commented that considering sensitivity, specificity, and predictive value is as important as the reference range when interpreting laboratory data.
Sherlita Amler
ATSDR
Dr. Amler, a pediatrician, stressed her observations of over-interpretation and misinterpretation of hair analysis results.
She noted that a lack of knowledge exists among health care providers in terms of how to use hair analysis, citing two examples. She described a case of an autistic child with reportedly high levels of mercury in his hair. The physician presumed that the elevations were due to his immunizations and ordered chelation in hopes of improving the autism. In another case, the interpretation of hair analysis results of a Down's Syndrome child as a dietary insufficiency led to the administration of high vitamin doses and an unusual diet. (Dr. Clarkson raised the point that misuse or misinterpretation of laboratory tests is not unique to hair analysis.)
Gary Campbell
ATSDR
Dr. Campbell emphasized the need to clearly define "normal" and
"reference" ranges and to describe how these ranges are developed
in the various laboratories. Understanding the meaning and derivation
of such ranges is very important to individuals who need to interpret
site-specific hair analysis results and understanding whether results
may be elevated. Further, Dr. Campbell questioned what is known
about possible geographical or regional differences in background
concentrations of various substances in hair.
Robert Jones
CDC
Dr. Jones requested that the panel and ATSDR consider the following:
Melody Kawamoto
CDC/National Institute for Occupational Safety and Health
Dr. Kawamoto presented a schematic that integrated many of the concepts
and issues being discussed by the panel (see
Figure 7-1). She explained the interface between the many compartments
within the body and how different testing methods help piece exposure
information together. Specifically, Dr. Kawamoto discussed how different
methods help assessors identify potential (environmental media sampling),
external (wipes, breathing zone air samples, hair), and internal
(hair, blood, urine) exposures to a particular substance and how
that information may be integrated to evaluate potential health
effects. She emphasized the importance of establishing a framework
under which to conduct exposure and health effects evaluations,
including clearly identifying the problem and the hypothesis under
which you will proceed, identifying study design issues, and understanding
sampling and analytical issues.
David Mellard
ATSDR
In reference to the arsenic conference held in San Diego in 2000, Dr. Mellard commented on a study in which a single volunteer showered in arsenic-contaminated water to help better understand internal versus external contamination. The study revealed that up to a certain level, no change in arsenic levels in hair were observed. Dr. Mellard suggested that perhaps further study is worthwhile to see if, for relatively low levels of arsenic in water, hair could be used as a measure of internal contamination, without worrying about external contamination.
Dr. Kosnett responded with a few words of caution: In vitro
experiments have shown that external absorption is dependent on
time. Therefore a single showering episode may not reflect a longer-term
exposure or exposure through bathing. Having reviewed the literature,
Dr. Kosnett
indicated that he is not convinced yet that any cut-off point exists
at which there is no element of external uptake of arsenic in hair
from bathing.
David Quig
Doctor's Data
Day #1
Dr. Quig, from Doctor's Data (a commercial laboratory), expressed
extreme gratitude for being invited to this meeting and offered
his opinion on a variety of topics related to analytical methods
and factors affecting the interpretation of laboratory results:
Day #2
Dr. Quig provided more comments toward the end of the second day
of the meeting. His stated opinions are summarized below:
Barry Sample
Quest Diagnostics
Dr. Sample speculated on the possible value of measuring wash solutions as well as washed hair in attempts to further distinguish between internal and external exposures. Wash solution may provide a better sense of external levels and the hair may provide a better indication of the total internal burden. At a minimum, Dr. Sample suggested incorporating wash evaluation into any standard protocol.
Based on his experience looking at drugs, Dr. Sample acknowledged that data may not exist to set the "normal range." In order to do so, one needs to understand the different rates and methods of incorporation into the hair. He suggested that there may be some value, in an occupational setting, in developing an individual reference range.
In response, Dr. Kosnett commented that workers may not be the best population to study for normal ranges because of the potential for external exposures in various work places. Dr. Seidel noted that further research is needed into the utility of studying wash water. Studies suggesting that easily removed fractions represent exogenous sources and the not so easily removed fraction represents endogenous sources have been disproved.
Michael Schaffer
Pyschemedics Corporation
Day #1
Dr. Schaffer, a trained industrial toxicologist with an interest in criminal justice and forensics, explained that Pyschemedics performs hair analysis as part of workplace drug testing. He asked participants to keep an open mind and consider the science of hair analysis very carefully. Knowledge gained from the last 10 years of testing hair for drugs of abuse can, he said, be used to enhance the knowledge base for using hair analysis for environmental/public health evaluations. He stressed that his experience in the drug testing arena has revealed that hair analysis is not totally unreliable. Good science and good analyses have supported legal cases. If the proper analytical tools and washing procedures are used, valid interpretations can be made.
Dr. Schaffer recognizes that drugs of abuse are different than trace metals. Working with mass spectrometry, metabolite profiling has helped identify uniquely internal measures of the substance of concern. It has taken 10 years, but such tools are now available.
Dr. Schaffer stressed that hair offers a unique matrix, recognizing that there is much that is not known or understood. In time, he feels, hair analysis will likely provide a lot of useful information.
Day #2
Dr. Schaffer expressed concern that some of the statements made
during the panel discussions could be misinterpreted or used inappropriately.
Specifically, he wanted to make certain that caveats were provided
with panel conclusion statements so that it is clear that hair analysis
for substances of abuse is appropriate and based on good science;
the conclusions drawn by the panel should apply to environmental
contaminants only.
Dr. Schaffer also responded directly to Dr. Baratz's overview of the Ditton paper.5 He took exception to the implication that hair analysis may not be suitable for testing drugs of abuse. He stated that conducting hair testing with the proper safeguards is defensible and has been upheld by the courts. He noted that no hair color or ethnicity bias exists. In vitro studies have shown incorporation of drugs in different types of hair, but those drugs can be removed by washing as quickly as they are bound to hair. The Department of Health and Human Services (Substance Abuse/Mental Health Services Administration) is currently writing draft guidelines for the incorporation of hair analysis into the federal workplace drug testing program. A pilot proficiency survey is also available to help address quality control issues; the model is urine drug testing.
Subsequent to the June 12—13, 2001, panel discussions, Dr. Schaffer submitted additional comments and supporting literature. He provided (1) a partial listing of those cases demonstrating judicial acceptance of the Psychemedics hair analysis method, (2) information on hair testing and racial or color bias, and (3) information on the effectiveness of Psychemedics' washing procedures for ruling out external contamination. (See Appendix G.)
Margaret Schonbeck
Colorado Department of Public Health and Environment
Ms. Schonbeck questioned whether hair analysis would be a valid consideration at an arsenic exposure site (soil pica/soil ingestion) where urine sampling is already planned.
Dr. Kosnett commented that a hair assay could reveal the potential
for exposure, but that environmental and urine data will have already
provided that information. It is not likely that hair analysis would
provide additional insight. Dr. Baratz re-emphasized that one must
examine the clinical utility before considering hair analysis. Does
it have any predictive value? Without symptom or disease history,
or unless you have a quantifiable dose-response relationship, hair
analysis data will not help. Dr. Baratz expressed concern that collecting
hair samples as another means of documenting exposure will only
muddy the waters. Dr. Seidel suggested collecting, analyzing, and
archiving the data, but being clear with the community up front
what the data can and cannot be used for. Dr. White emphasized the
distinction between medicine and public health, which can sometimes
cause confusion and tension in the community. That is, medicine
is looking at the individual and treatment options, while public
health is looking at populations and possible risk factors.
Anthony Suruda
Association of Occupational Environmental Clinics
Rocky Mountain Center for Occupational and Environmental Health
Dr. Suruda questioned whether nails are more susceptible to external contamination by metals than hair. In response, Dr. Kosnett noted that, in some forensic investigations, the distal portions of nails have shown correlation with poisoning. Some studies have investigated whether the inner surface of the nail may be less likely to contain elevated levels of arsenic as a result of external contamination. Study findings suggest that external contamination of nails is an issue as it is in hair. For example, a study that measured arsenic in nails over time following arsenic ingestion revealed the following: (1) elevated levels of arsenic were measured in distal segments of unscraped nails (believed to be deposited by sweat); (2) scraped nails during the same period did not reveal elevated levels; and (3) samples of scraped nails taken later in time showed elevated arsenic levels (as a result of the ingestion episode). As with hair, it is questionable whether methods exist to clearly distinguish between externally and internally deposited contamination.
Dr. Suruda indicated that he was requested to evaluate an individual with peripheral neuropathy 9 months after possible exposures to lead and arsenic. Total arsenic urinalysis had been performed closer to the time of exposure, but not a fractionated analysis. To evaluate past exposures, a toenail sample was taken down to the growth plate, which was negative. These results were used to conclude that the individual had not been exposed to arsenic within the past year.
Dr. Suruda noted that the charge to the panel was to examine aspects of hair analysis related to public health assessments. Dr. Suruda commented that he is more often faced with questions from individuals (practitioners, community members) looking for assistance in interpreting hair analysis results. He expressed hope that the panel and ATSDR will consider the utility of hair analysis in the assessment of public health as well as for individual assessment. Dr. Suruda noted that ATSDR's toxicological profiles and other agency documents have great credibility within the scientific community and that he looks forward to further guidance (e.g., biological monitoring guidelines) to assist in his evaluations. Even if all the answers are not available, Dr. Suruda said, hair analysis should be ranked with other methods of monitoring (e.g, blood, urine).
Regarding research needs, Dr. Suruda indicated the need for a
population-based study on how hair analysis is used and what impact
it has had. Questions to consider include: Can it be used to identify
poisoned individuals? How many people are unnecessarily alarmed
or mistreated on the basis of hair analysis? What type of reports
do practitioners receive on hair analysis? Dr. Suruda expressed
concern regarding what he referred to as "junk science." For example,
he pointed to a laboratory report that indicated "lead is slightly
above detection limit" and that the "zinc to mercury ratio is extremely
high." The report indicated that these ratios do not indicate disease;
however, it also indicated that research has shown that this "will
eventually lead to other disturbances in metabolic function." Physicians
and other practitioners need to recognize that they do not often
know what results mean and should be cautious in what they report.
5Dr. Baratz clarified that his purpose in presenting the Ditton paper was to summarize some of the key aspects and possible pitfalls of hair analysis. Dr. Baratz noted that the author, a chemist, has done studies on drugs of abuse and has shown the validity of hair analysis for testing drugs of abuse.