Hair follicle tests, often used for drug screening, do not actually test the hair follicle itself. Instead, they analyze a clipped strand of hair removed from the head.
How Hair Follicle Testing Works
Sample Collection
- A small amount of hair is cut using scissors close to the scalp.
- The hair sample is typically taken from the back of the head where the hair is less noticeable.
Lab Analysis
- The collected hair strand is sent to a laboratory.
- The hair sample undergoes chemical analysis to detect traces of drugs or their metabolites.
- The test can identify drug use within approximately the last 90 days.
| Test Type | Sample Material | Analyzed |
|---|---|---|
| Hair Follicle Test (Commonly known) | Clipped hair strand | Drug use in the past 90 days |
What it Doesn't Test
It's important to note that, despite the common name, this test doesn't examine the actual hair follicle. The follicle is located under the scalp, and the test instead relies on the chemical analysis of the hair strand. The analysis looks for traces of drugs or their metabolites that have been deposited into the hair as it grows.
