Laboratory based drug testing- This is the type of testing conducted by the vast majority of employers in the United States. Laboratory drug testing services are available for the different substances, like: urine, oral fluid and hair.

The urine drug testing involves collecting a urine sample and sending this sample to a Certified drug testing laboratory. Once received at the laboratory an initial test is conducted to detect the presence of drugs above a standard threshold level. If no tested drugs are detected above the threshold level, the sampling is complete and the "negative" results are sent to the company. If any tested drugs are detected above the threshold level, the sample moves on to confirmation testing. This testing will determine the quantitative level of the drug and is then reported to the company as a "positive" if it exceeds the standard threshold level.

Hair follicle testing- This is another extremely efficient method of detecting even the smallest traces of many different kinds of drugs. The hair follicle testing, also known as hair drug testing, has many benefits over other methods of testing. First, it ensures higher accuracy as compared to urine samples because hair generally tends to stay in human body for much longer period than urine. Thus, it can detect any drug intake ranging from sixty to ninety days. Second, sample collection is less invasive as compared to urine sample collection. The hair strands are tested in the laboratory and results can be obtained in one to three days. It's efficient enough to test many different kinds of drugs.