The scientific community currently does not know the range of contamination levels typically found in human hair.
Without reliable data in the peer-reviewed literature on baseline or background hair contamination levels in the general
population, health agencies cannot determine if hair analysis results from a given site are unusually high or low, unless
hair samples were collected from comparison populations.
A critical input into public
health assessments is an
What can hair analysis tell me about exposure?
understanding of the dose,
For most substances considered as contaminants, hair analysis offers
whether measured or esti-
virtually no quantitative insights into exposure doses. Qualitative insights
mated. Because we currently
know too little about rates at
might be gleaned from certain studies.
which substances in our
bodies distribute into hair, it is
impossible to calculate internal doses from hair sampling results. Therefore, hair analysis would provide no added
insight beyond the estimates of exposure dose calculated from the use of default exposure assumptions in conjunction
with the detected concentrations of substances in air, soil, and water.
Can hair analysis results be used to predict adverse health effects?
With very few exceptions, hair analysis results provide no insights as to whether an individual will develop adverse health
effects. Several limitations prevent health professionals from using hair analysis results to make scientifically defensible
public health conclusions:
With one exception, ATSDR is unaware of any conclusive studies that link hair concentrations of contaminants to
specific health outcomes. Health professionals therefore have no scientific basis for deciding whether a particular hair
analysis result would be associated with adverse health effects. As the exception, scientists have studied how hair
concentrations of methyl mercury in pregnant mothers relate to adverse developmental effects in their children.
Because little is known about the transfer kinetics of contaminants into hair, scientists have not been able to
develop models that can use a hair analysis result to predict concentrations of contaminants in other biological media
(e.g., blood). Thus, health
professionals cannot use a hair
What can hair analysis tell me about health effects?
analysis result to compute a
body burden, an internal dose,
With the exception of methyl mercury, hair analysis results currently
or other parameter that would
provide no meaningful insights on whether an individual will develop
enable a meaningful toxico-
adverse health effects.
logic evaluation of a hair
analysis result.
Under what circumstances should hair samples be collected?
Whether hair samples should be collected at a given site depends on the questions that you ultimately want to answer.
ATSDR strongly encourages health professionals to develop clear study objectives and then critically evaluate whether
hair analysis will help achieve those objectives. We recommend asking the following two questions before considering
hair analysis:
What conclusions will I be able to draw from a positive or negative test result?
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