General Public
Hair Sample Testing:
What can hair sampling results tell me about environmental exposures?
ing hair analysis. Therefore, it is possible that two laborato-
Sometimes health professionals can check whether people
ries will report different results for hair samples collected
have been exposed to chemicals in the environment. For
from the same person. The different approaches used to
example, levels of chemicals can be measured in the soils,
collect and analyze hair samples make it very difficult for
drinking water, and air where people live and work, and
health professionals to know what the results of any indi-
from these measures the amount of chemicals that people
vidual hair sample really means.
might routinely contact can be estimated. For some chemi-
cals, urine and blood samples can be collected from people
to look for evidence of actual exposure. In recent years,
If a substance is detected in my
health professionals have debated what hair samples can tell
hair, does that mean I have been
us about environmental exposure. In this fact sheet, the
Agency for Toxic Substances and Disease Registry (ATSDR),
exposed to environmental
a public health agency of the U.S. Department of Health
and Human
Summary
Services, looks at
how best to
Not necessarily. Generally, substances can end up in your
ATSDR believes many scientific
interpret results
hair in two ways. First, chemicals already in your body may
issues need to be resolved before
from human hair
get into your hair. These chemicals might have been in
hair analysis can become a useful
samples to
something you ate, the water you drank, or the air you
tool to understand environmental
evaluate environ-
breathed. Alternatively, the source of the chemicals could
exposures. Although hair analysis
mental exposures.
be from other exposures, or they could simply occur
may answer some questions
naturally in your body. Second, chemicals outside your
about environmental exposure to
Currently, hair
body, like those in dust particles and hair care products,
analysis is used for a few substances, hair analysis
might stick to your hair after coming into contact with it.
often raises more questions than it
purposes other
answers.
than assessing
Given how often most people cut their hair, hair analysis
environmental
generally will not tell you anything about exposures that
exposures. For
occurred more than one year ago. Furthermore, for most
example, hair analysis has been used to test for illegal drug
chemicals, hair analysis cannot tell you where a chemical in
use and to conduct criminal investigations. This fact sheet
your hair came from. More specifically, when a chemical is
does not address these other uses.
detected in your hair, we often cannot tell if it is from a
contaminated waste site, from your diet, or from other
sources. This makes it very difficult to understand what a
are
What are hair samples and
positive test result for a chemical in your hair truly means.
hair analyses?
Do health professionals
Do
A hair sample is a collection of hair strands, which are most
commonly use hair analysis
commonly cut from a person's head. Hair samples usually
to diagnose health problems?
contain hair that has grown over the last 12 months. Al-
though hair growth varies, 12 months of hair growth usually
represents about 5 inches of hair. Hair analysis occurs when
laboratories measure the amount of specific substances in
not know enough right now to use someone's hair analysis
the hair sample.
results to predict if health problems will occur. In fact, for
many chemicals, we do not even know the range of levels
Unfortunately, no widely accepted standards specify how
that are typically found in the hair of an unexposed person.
hair samples should be collected, stored, and analyzed, and
Without this information, we cannot tell if one person's hair
different laboratories use different methods when conduct-
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