What are the Different Types of Drug Screening Tests?

The most common drug screening tests used to detect substances in the body are urine tests and blood analysis. Drug screening tests that use hair strans and saliva also can be performed. Some drug testing is completed in a laboratory, medical office or hospital setting, but many drug tests can be given anywhere. Sometimes people purchase at-home drug tests to check their own results or the results of someone else in the home.

For the most basic type of drug testing, a five-panel drug screening test can be used. It detects the presence of the five most commonly abused street drugs. Usually, the five-panel test includes the detection of cocaine, marijuana, amphetamines, opiates and phenylcyclohexylpiperidine (PCP), also known as "angel dust."

A more comprehensive test is aptly named the 10-panel drug screen. The detection of drugs such as methamphetamine, methadone, barbiturates, benzodiazepines and tricyclic antidepressants normally is included in this type of test. The drugs detected in a five-panel drug screening also are detected in the 10-panel test.

Urine tests are the most frequently used and cost-effective drug screening method. Rapid results — usually in less than 10 minutes — make the urine test quick and convenient. The urine test will show what, if any, of the tested drugs are in the subject's system.

The urine test is ideal for detecting drugs in the body, but it will not specify how long ago the patient took the drug. It will not show if he or she was under the influence at the time the urine sample was given, either. Urine tests can detect drugs for most substances within two to three days of their use. Marijuana can be detectable for a longer period of time.

Saliva tests usually can provide the same results in the same amount of time as urine drug screening tests. Results show up on the test stick within minutes. In the event of a positive reading, however, the test piece needs to be sent to a laboratory. Confirmation of a positive result can take several days. For that reason, it is not used as commonly.

Blood tests are the most accurate form of drug screening tests. They also are the most invasive. These tests can check for all types of drugs, alcohol and even tobacco. Unlike the urine test, a blood test usually can determine whether the patient was under the influence of drugs at the time of the test. A blood test often is used in hospitals to gauge whether the patient is under the influence, especially after a serious accident.

Hair strand drug screening tests are not as common as urine or blood testing. These tests work by analyzing a strand of the patient's hair for trace amounts of certain drugs. The hair sample typically is taken from the head, but it can come from anywhere on the body.

Depending on the length of the hair sample, several years of drug history can be obtained. Small traces of drug molecules naturally collect in the hair strand over time. The laboratory can calculate what drugs were ingested, how long ago and how much of the drug was taken. The hair test is most effective in determining a longer history of drug use, but it can lack in detecting the most recent drug use.