Hair analysis can be used to check if people are blood relatives. Forensic hair analysis can be done to help identify a criminal by evaluating hair structure and DNA from cells attached to the root of the hair. Hair samples are tested with specific chemicals and looked at under a microscope. Hair analysis can also be used to check for poisoning caused by metals such as lead or mercury. But hair analysis alone usually is not used for this type of testing.
Hair is a protein that grows out of hair follicles in the skin. Normally, a hair grows in the hair follicle for many months, stops growing, and falls out. A new hair then grows in the follicle. It takes weeks for a hair sample to show changes in the body, because hair grows slowly. Hair samples do not show recent changes in the body, such as drug use within the past few days. But a hair analysis may show drug use or exposure to chemicals that occurred over the last few months.
Why It Is Done
Hair analysis is used to provide DNA evidence for criminal and paternity cases. For DNA testing, the root of one hair is needed to analyze DNA and to establish a person's genetic makeup.
Hair analysis is less commonly used to test for heavy metals in the body, such as lead, mercury, and arsenic.
How To Prepare
If you have a hair analysis done, the laboratory will give you specific instructions on how to prepare your hair. Hair preparation and the part of your body from which the hair is taken varies. In general, your hair should be washed and free of any hair care products.
You may be asked to sign a consent form that says you understand the risks of the test and agree to have it done.
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results may mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).