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Usefulness of Measurements of Trace Elements in Hair

Elemental analysis of hair might seem to be an attractive approach to the assessment of trace element status. Sample collection is noninvasive and, once obtained, further handling is simple and straightforward. Concentrations of trace elements in hair are often considerably higher than in blood or other samples and subsequent analysis should, therefore, be easier and more precise. Because of the physiology of hair formation, analysis of the total length should give an integrated assessment of exposure over a known period of time, while examination of longitudinal sections should provide a diary or calendar. Noteable examples of the way in which hair analysis has been applied to exotic problems, e.g. arsenic and the death of Napoleon, have led to an unsubstantiated public confidence in this technique. Newly developed methods, e.g. inductivelycoupled plasma atomic emission spectrometry, allow for the simultaneous determination of up to approximately 30 elements in hair following a simple acid digestion. These features, together with an increased perception by the public of matters of diet and health, has led to a growing number of commercial organisations offering a hair analysis service. Such companies often make extravagant claims, based on limited scientific data for what can be revealed by such analysis. Thus, requests are being received by physicians and hospital biochemists for guidance on the interpretation of results and the follow-up of anxious, indeed frightened, patients whose 'trace element imbalance' has been discovered by hair testing. This phenomenon may best be illustrated by a typical case description. A middle-aged man visited his general practitioner after receiving the results of a hair test which reported an increased concentration of