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The Society for Minerals and Trace Elements
Statement
J. Trace Elements Med. BioI. Vol. 10. p. 202 (1996)
The Society for Minerals and Trace Elements Gesellschaft fUr Mineralstoffe und Spurenelemente e.V. (GMS) Limitations of Trace Element Analysis in Hair Trace elements are located in hair at different concentrations depending on the distance from the root of the hair. They derived from I. the matrix during histogenesis 2. the deposit of sebum 3. transfer from exocrine sweat glands by absorption or other mechanisms 4. incorporation of apocrine sweat glands directly into the hair 5. pollution deposit around the hair after extrusion of hair by the skin 6. residue of cosmetic or pharmaceutical products on piliferous skin Because of these facts numerous endogenous influences. exogenous interferences and analytic details have to be taken into consideration when trace elements are determined in hair. Endogcnous h!f7uellces: The concentration of trace elements in hair is considerably influenced by age, race, sex, diet, medication, location from where the hair was cut, length of the hair, and colour others more. All these factors have to be taken into account for the establishment of reference values. Exogcnous Interferenccs: Mainly shampoo, colorants, body lotions, cosmetics and other environmental intluences have to be considered. From the environmental health point of view information on the living and working place and leisure-time activities are essential. The outer epidermis of a hair is not an impermeable layer. Very small fissures and orifices facilitate immigration and deposition of chemicals. The same applies for the protein structure of hair. where components of shampoos, cosmetics or tap water may be absorbed and deposited. Therefore, hair contains elements both of endogenous and of exogenous origin. Solvents are used for preanalytical hair sample preparation. These solvents, however, can't differentiate between the body's own deposits and from potential environmental contaminants. By solvent extraction relevant and irrelevant information may equally be removed. Elements which were primarily loosely bound to the hair surface, may get fixed to the hair structure by the preanalytical decontamination procedures. Hair can be regarded as a kind of ion exchanger with its small superficial holes and fissures operating as ports of entry. Precision and Reproducihility: When the trace element contents of hair samples of practically identical origin are determined, imprecisions of more than 30% are commonly obtained. This poor result is based less on imprecisc analytical methods than on the unusuability of the material tested. Even when the prerequisites for an accurate analysis (careful calibration for every element to ensure sufficient sensitivity and specificity) is satisfied, the precision of
hair analysis is certainly not guaranteed. Spectrometric methods need a clear definition of spectral wavelength, energy and mass; the analytical criteria are without any value, if the analytical matrix is heterogeneous and compromised by exogenous contamination. Rejerence Methods and Normal Values: There is an urgent need for standardisation and routine adaptation of reference methods and normal values. The methods currently used have largely differing limits of detection and specific elemental properties. For a single element analysis atomic absorption spectroscopy (AAS) is often used. Unfortunately no standardized and generally accepted recommendations for this procedure exist. The situation with ICP-AES multielement analysis is better. But the problematic background correction - contrary to AAS - may induce unreliable analytical results. The normal values used by different laboratories for hair vary widely. The lack of comparability and differing recommendations for trace element supplementation raise various questions. The normal values used are generally "home-made", difficult to monitor and they differ largely from laboratory to laboratory. The National Institute of Environmental Studies (NlES) of the Japan Environment Agency, tried to define by a large-scale study the lacking reference for human hair. The results were very disappointing, and unacceptable. because of the extreme scattering. Interlahoratory Comparison: The International Atomic Energy Agency (IAEA) performed a interlaboratory quality assessment of 66 laboratories in 28 countries. The trial yielded 2500 results, which proved to be useless. The National Bureau of Standards (NBS) of the USA inaugurated a similar study, which was stopped, however, before publication of the results. The American Society of Elemental Testing Laboratories (ASETL) tested the reliability of hair analysis in an external quality trial. This program discovered considerable defects, mainly because of the large scattering of results. Furthermore the imprecisions of the laboratories evaluated, which had received several identical hair samples under different code numbers. were extreme. Conclusions: The information on the trace elemental supply of the human body derived from hair analysis is not reliable enough to detect metabolic defects or to define the cause of a deficiency disease. The subsequent assessments and interpretation of the results lead to questionable therapy measures and dietary experiments. which are offered to persons in good faith at high cost. For all these reasons serum. plasma or whole blood remain the most logical and reliable test materials. As long as hair diagnostics is not optimized. shortcomings are not eliminated, and unprofessional analyst confuse patients, the critics of hair analysis have be far the better arguments.
K-J Reference requests to the General Secretary
Board of the executives President: Prof. Dr. Wilhelm Fresenius Institut Fresenius, Chemische und Biologischc Laboratorien GmbH, 1m Maisel 14, D-65232 Taunusstein, Germany. Vice Presidents: Prof. Dr. Peter Bratter Hahn-Meitner Institut Berlin, Abt. Spurenelemente in Gesundheit und Ernahrung, Glienicker Str. 100,0-14109 Berlin, Germany. Prof. Dr. Heinz Liesen Sportmedizinischcs Institut der Universitlit Paderborn, Warburgcr Str. 100,0-33098, Germany. General Secretary: Prof. Dr. Dr. Klaus Diirner Stadtisches Krankcnhaus Kiel, Zentrallaboratorium, Chemnitzstr. 33. 0-24116 Kicl, Germany. Tel. ++49 (0431) 1697 347. Fax. ++49 (0431) 1697409 Chairman of the Scientific Committee: Prof. Dr. Hirgen D. Kruse-Jarres Katharinenhospital. Arztlicher Direktor, Kricgsbergstr. 60, D-70174 Stuttgart. Germany. - - - - - - - - - - - - - - - - ,------,--,
© 1996 hy Gustav Fischer Verlag Stuttgart· lena' New York
J. Trace Elements Med. BioI. Vol. 10. p. 202 (1996)
The Society for Minerals and Trace Elements Gesellschaft fUr Mineralstoffe und Spurenelemente e.V. (GMS) Limitations of Trace Element Analysis in Hair Trace elements are located in hair at different concentrations depending on the distance from the root of the hair. They derived from I. the matrix during histogenesis 2. the deposit of sebum 3. transfer from exocrine sweat glands by absorption or other mechanisms 4. incorporation of apocrine sweat glands directly into the hair 5. pollution deposit around the hair after extrusion of hair by the skin 6. residue of cosmetic or pharmaceutical products on piliferous skin Because of these facts numerous endogenous influences. exogenous interferences and analytic details have to be taken into consideration when trace elements are determined in hair. Endogcnous h!f7uellces: The concentration of trace elements in hair is considerably influenced by age, race, sex, diet, medication, location from where the hair was cut, length of the hair, and colour others more. All these factors have to be taken into account for the establishment of reference values. Exogcnous Interferenccs: Mainly shampoo, colorants, body lotions, cosmetics and other environmental intluences have to be considered. From the environmental health point of view information on the living and working place and leisure-time activities are essential. The outer epidermis of a hair is not an impermeable layer. Very small fissures and orifices facilitate immigration and deposition of chemicals. The same applies for the protein structure of hair. where components of shampoos, cosmetics or tap water may be absorbed and deposited. Therefore, hair contains elements both of endogenous and of exogenous origin. Solvents are used for preanalytical hair sample preparation. These solvents, however, can't differentiate between the body's own deposits and from potential environmental contaminants. By solvent extraction relevant and irrelevant information may equally be removed. Elements which were primarily loosely bound to the hair surface, may get fixed to the hair structure by the preanalytical decontamination procedures. Hair can be regarded as a kind of ion exchanger with its small superficial holes and fissures operating as ports of entry. Precision and Reproducihility: When the trace element contents of hair samples of practically identical origin are determined, imprecisions of more than 30% are commonly obtained. This poor result is based less on imprecisc analytical methods than on the unusuability of the material tested. Even when the prerequisites for an accurate analysis (careful calibration for every element to ensure sufficient sensitivity and specificity) is satisfied, the precision of
hair analysis is certainly not guaranteed. Spectrometric methods need a clear definition of spectral wavelength, energy and mass; the analytical criteria are without any value, if the analytical matrix is heterogeneous and compromised by exogenous contamination. Rejerence Methods and Normal Values: There is an urgent need for standardisation and routine adaptation of reference methods and normal values. The methods currently used have largely differing limits of detection and specific elemental properties. For a single element analysis atomic absorption spectroscopy (AAS) is often used. Unfortunately no standardized and generally accepted recommendations for this procedure exist. The situation with ICP-AES multielement analysis is better. But the problematic background correction - contrary to AAS - may induce unreliable analytical results. The normal values used by different laboratories for hair vary widely. The lack of comparability and differing recommendations for trace element supplementation raise various questions. The normal values used are generally "home-made", difficult to monitor and they differ largely from laboratory to laboratory. The National Institute of Environmental Studies (NlES) of the Japan Environment Agency, tried to define by a large-scale study the lacking reference for human hair. The results were very disappointing, and unacceptable. because of the extreme scattering. Interlahoratory Comparison: The International Atomic Energy Agency (IAEA) performed a interlaboratory quality assessment of 66 laboratories in 28 countries. The trial yielded 2500 results, which proved to be useless. The National Bureau of Standards (NBS) of the USA inaugurated a similar study, which was stopped, however, before publication of the results. The American Society of Elemental Testing Laboratories (ASETL) tested the reliability of hair analysis in an external quality trial. This program discovered considerable defects, mainly because of the large scattering of results. Furthermore the imprecisions of the laboratories evaluated, which had received several identical hair samples under different code numbers. were extreme. Conclusions: The information on the trace elemental supply of the human body derived from hair analysis is not reliable enough to detect metabolic defects or to define the cause of a deficiency disease. The subsequent assessments and interpretation of the results lead to questionable therapy measures and dietary experiments. which are offered to persons in good faith at high cost. For all these reasons serum. plasma or whole blood remain the most logical and reliable test materials. As long as hair diagnostics is not optimized. shortcomings are not eliminated, and unprofessional analyst confuse patients, the critics of hair analysis have be far the better arguments.
K-J Reference requests to the General Secretary
Board of the executives President: Prof. Dr. Wilhelm Fresenius Institut Fresenius, Chemische und Biologischc Laboratorien GmbH, 1m Maisel 14, D-65232 Taunusstein, Germany. Vice Presidents: Prof. Dr. Peter Bratter Hahn-Meitner Institut Berlin, Abt. Spurenelemente in Gesundheit und Ernahrung, Glienicker Str. 100,0-14109 Berlin, Germany. Prof. Dr. Heinz Liesen Sportmedizinischcs Institut der Universitlit Paderborn, Warburgcr Str. 100,0-33098, Germany. General Secretary: Prof. Dr. Dr. Klaus Diirner Stadtisches Krankcnhaus Kiel, Zentrallaboratorium, Chemnitzstr. 33. 0-24116 Kicl, Germany. Tel. ++49 (0431) 1697 347. Fax. ++49 (0431) 1697409 Chairman of the Scientific Committee: Prof. Dr. Hirgen D. Kruse-Jarres Katharinenhospital. Arztlicher Direktor, Kricgsbergstr. 60, D-70174 Stuttgart. Germany. - - - - - - - - - - - - - - - - ,------,--,
© 1996 hy Gustav Fischer Verlag Stuttgart· lena' New York