Normal ranges of hair minerals have not been defined. For most elements, no correlation has been established between hair level and other known indicators of nutrition status. The use of a single multielemental hair analysis test as the sole means of diagnosis violates basic tenets of medical practice that laboratory findings should be considered together with the patient's history and physical examination, and that the practitioner should keep in mind that laboratory errors occur. For these reasons, multielemental analysis of human hair is not a valid technique for identifying an individual's current bodily excesses or deficiencies of essential or nonessential elements. In the mid-1980s, there were about 18 laboratories doing commercial hair analysis in the United States.
Today there are fewer.
However, at the end of the year, the testing service refused to continue because the data were inconsistent and appeared to have no clinical significance. In 1985, I sent paired samples from one of the girls to five more labs. The reported levels of most minerals varied considerably between identical samples sent to the same laboratory, and from laboratory to laboratory. Most of the reports contained computerized interpretations that were voluminous and potentially frightening to patients. The nine labs that included supplement advice in their reports suggested them every time, but the types and amounts varied widely from report to report and from lab to lab.