The concentration of minerals in the hair provides useful information of recent metabolic events concerning nutritional intake and toxic metal exposure (internal or external).
The validity of mineral results obtained from hair is only as good as the sample that is used. It is imperative that samples are properly obtained to insure proper interpretation of the results. The clinician should be thoroughly familiar with proper sampling of specimens and should have strict control over obtaining hair samples from patients, otherwise the test results may have little clinical significance.
The accuracy of any laboratory test is largely dependent upon properly obtained samples submitted for testing. Improper sampling techniques can compromise test results regardless of how sensitive and sophisticated the analytical instrumentation used. If proper collection protocols for obtaining hair samples for mineral testing are not followed, the clinical validity of the trace element results can be markedly compromised. Much of the critical opinions and skepticism concerning hair tissue mineral analysis (HTMA) has been based upon erroneously derived data due to improper sampling protocols.
The vast majority of HTMA research is based upon data obtained from scalp samples. Likewise, the reference intervals and interpretation of HTMA at trace elements are based upon results obtained from properly collected scalp samples. Proper sampling requires that the hair specimen be taken in small portions from different areas of the scalp (mid-parietal to the occipital region). The reason for collecting samples from several different locations is due to the variation in the growth and/or resting phase of hair follicles. [The Molecular and Structural Biology of Hair. Steen, K, et al, Eds. Annals of the NY Acad. of Sci. Vol.642, N.Y.1991]
It is known that the test results of samples taken from only one location can be different when compared to a sample taken from a different location. Therefore, it is critical that multiple sample locations are used in order to give a better representation of the most recent metabolic events. In addition, care should be taken to insure there are no chemical residues on the hands or instruments when taking a sample: Scissors used for cutting samples should be of high-grade stainless steel and free of any type of residue. It should be noted that there have been numerous incidences of contamination of samples from the use of low-grade metal scissors that have deteriorated.
Approximately 250 milligrams of hair is required for a complete trace element panel. The hair should be cut at the scalp and the sample submitted for analysis should be no longer than 1.5 inches (4cm). If a person's hair is several inches long, the ends beyond 1.5 inches should be cut and discarded as the clinical validity of test results from the ends of the hair can be markedly compromised.
Hair analysis is a reasonable and inexpensive first step toward diagnosing heavy metal toxicity.