What is a 4 panel hair follicle test?

A 4-panel hair follicle test is a type of drug screening that analyzes a small sample of hair to detect the presence of specific substances. Typically, it tests for four categories of drugs, which may include marijuana, cocaine, opiates, and amphetamines. This method can identify drug use over a longer period, generally up to 90 days, as substances are incorporated into the hair as it grows. It's often used in employment screenings, legal cases, or rehabilitation programs.