At the time of this study, there were three commercial institutions conducting hair mineral analysis in Korea. Two of them are based on Korea, and one is a branch of a large laboratory headquartered in the USA, which receives samples from Korea for analysis. All three laboratories were included in this study.

Hair was donated by a 23 year-old healthy, black-haired, Asian man. He had no medical or drug history. Routine blood tests and serum levels of copper, zinc, iron and magnesium were within the normal limits. Electrocardiogram (EKG) and chest radiograph were normal. This study was approved by the Institutional Review Board of the Dankook University Hospital, and the hair donor provided informed consent prior to participation.

Hair was cut adjacent to the scalp from several areas of the parieto-occipital regions, using clean stainless steel scissors. Hairs measuring 3 cm from the scalp were included. Collected hairs were intermingled, weighed, and divided into 6 groups according to the amounts required by each laboratory, ranging from 60~80 mg. For each laboratory, two divided samples were submitted at the same time with different IDs.

Differences among laboratories were analyzed by Friedman analysis of variance, using the mean value of two results at each laboratory. Differences between intra-laboratory data were analyzed by the Wilcoxon signed rank sum test. In all analyses, SPSS for windows (version 12.0; SPSS Inc., Chicago, IL, USA) was used. Data were valued within a confidence interval of 95%. A p-value of less than 0.05 was considered statistically significantly different (p<0.05).

The features of the laboratories are summarized in Table 1. All 3 laboratories analyzed hair samples with inductively coupled plasma mass spectrometry (ICP-MS). The advantage of ICP-MS is its lower detection threshold compared to inductively coupled plasma atomic emission spectrometry (ICP-AES). The required quantity for analysis at each laboratory was 60, 60 and 80 mg, respectively. Laboratory A analyzed 30 elements, and B and C analyzed 26 and 38 elements, respectively. In total, 24 elements including aluminum, arsenic, barium, bismuth, cadmium, calcium, chromium, cobalt, copper, iron, lead, lithium, magnesium, manganese, molybdenum, mercury, phosphorus, potassium, selenium, sodium, sulfur, uranium, vanadium, and zinc were commonly analyzed by all 3 laboratories. Laboratories provided numerical results and interpretation, which included an evaluation of health status, prediction of possible illnessess in the future, and recommendation on dietary habit. Two laboratories (B, C) added promotions of branded supplements according to the results.

Each laboratory presented a normal reference range for each analyzed element. They were summarized in Table 2. In many elements, all 3 laboratories used different reference ranges, based on studies. As seen in Table 2, the inter-laboratory differences of the reference range for several elements were sufficiently wide in that they did not overlap.

The laboratories presented their results on split hair samples as illustrated in Table 3. Statistically, the Friedman test of variance indicated no significant difference between different numerical results from 6 samples (p=0.513).

In the interpretation of their own results, the laboratories did not reach a general consensus although their numerical results were coherent, due to different reference ranges. As summarized in Table 4, laboratory A commented that the donor lacked iron and selenium. Laboratory B identified a cobalt, copper, selenium, zinc and phosphorus deficiency. According to laboratory C, the donor was only deficient in molybdenum. As a result, these differences resulted in the laboratories recommending different nutritional supplements and treatments to the hair donor.

The laboratories did not reproduce identical results, but statistically they were coherent numerical results according to the Wilcoxon signed rank sum test (p=0.513).

On interpretation, laboratory B failed to produce consistent results. B detected a cobalt, copper, selenium, and zinc deficiency in one hair sample, and a deficiency in cobalt, copper, selenium, and phosphorus in another one.

The laboratories indicated that the donor might experience symptoms such as chronic fatigue, dizziness, insomnia, depression, and anxiety. They also claimed he was at increased risk of developing osteomalasia, skin disease, arthralgia, anemia, hypercholesterolemia, alopecia and myalagia. In actuality, the donor did not experience health problems, and his blood test, EKG, and chest radiograph were unremarkable. Specifically, his serum levels of copper, zinc, iron, and magnesium was normal, but his iron level was below the normal limit according to laboratory A. Laboratory B concluded that he was copper and zinc deficient (Table 5).