Hair analysis is a controversial test that has used for many years by some alternative practitioners to assess a person's nutritional status and exposure to metals and minerals such as mercury.
A 2001 study published in the Journal of the American Medical Association, however, revealed that a hair sample from one person could produce extremely variable results when analyzed by six of the major hair analysis labs.
To be certified in the United States under the Clinical Laboratory Improvement Act (CLIA), labs are required to provide standardized clinical lab tests or use other methods to ensure the accuracy of their tests.
None of the labs in the study, all of which claimed CLIA certification, mentioned any procedure to verify the reliability of test results. For the single hair sample, variability among lab results ranged from 9.8% for sulfur to 238.1% for phosphorus.
This inconsistency may be partially attributed to contamination by hair dye, perms and other environmental chemicals. All six labs used a variety of methods to remove external contamination, however, no standardized procedure for hair sample collection and preparation exists to ensure consistency and reliability. How much of the lab results were due to external chemicals coating the hair or penetrating the hair shaft from the outside is unclear.
Reference ranges, values considered normal for a person's age, environment, and hair quality, also varied widely between laboratories. For example, one lab considered normal lithium values to be 1.25 to 3 while another considered normal to be 0.0035 to 0.025, ranges that don't even overlap.
Why use hair analysis at all? Minerals and potential toxins are present in very dilute amounts in blood. According to proponents of hair analysis, blood bathes growing hair follicles, so these minerals and metals become incorporated into the hair's protein.
Proponents also believe that minerals and metals can concentrate in the hair at several hundred times higher the levels found in blood. Although minerals such as calcium, chromium, selenium are among the more commonly analyzed minerals, not all elements in hair are considered to accurately reflect levels in the body.
Although further research may be needed to examine the validity of using the hair analysis test in different clinical situations, this study underlined the even greater need to establish standardized lab protocols and reference ranges.Sources:
Barrie S. Heavy metal assessment. Textbook of Natural Medicine. Edinburgh 2000. Churchill Livingstone, 161-175.
Markus S. Mineral status evaluation. Textbook of Natural Medicine. Edinburgh 2000. Churchill Livingstone, 211-215.
Seidel S, Kreutzer R, Smith D, McNeel S, Gilliss D. Assessment of commercial laboratories performing hair mineral analysis. JAMA 2001; 285: 67-72.
Steindel SJ, Howanitz PJ. The uncertainty of hair analysis for trace metals. JAMA 2001;285:83-85.