Interpreting quantitative analysis of hair samples for substance use involves understanding the relationship between detected drug concentrations and reported cutoff levels. This analysis provides an estimated history of drug use over a period of approximately 90 days, depending on hair length. For example, a higher concentration of a substance typically suggests more frequent or heavier use during the testing window. Laboratories often provide results with numerical values representing the concentration of each substance found, accompanied by designated cutoff levels for positive, negative, and sometimes inconclusive results.
This method of drug testing offers a broader detection window compared to urine or blood tests, which can be valuable in various situations, including pre-employment screening, legal proceedings, and clinical monitoring. Understanding the context of these results is essential for accurate interpretation. Over time, the development and refinement of analytical techniques have enhanced the accuracy and reliability of hair follicle drug testing.