The most common method for detecting if a person has taken a medication recently is to perform a drug test. Drug tests are routinely used by businesses, government agencies and healthcare facilities to screen prospective and current employees for drugs.

Blood tests provide the most accurate results for overdoses or poisoning. The extent of an overdose can be determined and the best treatment options can be administered with the information obtained from a blood test. Urine tests are commonly used to detect that may have been used days or weeks before the test. Urine tests are not as accurate as blood tests. There is a chance that a false negative or false positive result can occur if the patient takes certain prescription medications or herbal supplements. A patient should be asked to disclose any prescription medications, herbal remedies or over-the-counter medications.

If a urine test comes up positive for drugs the test should be retaken for that specific medication. Retaking the test will help to confirm the results and will help to identify a false positive result that might have caused the first test to test positive. A blood test can be done to determine if a drug was used recently or how much of the drug is in the system.

Drug testing can only identify if the individual has used or has been exposed to a drug during a certain span of time. A drug test cannot show the frequency of drug use or the degree of the user’s dependency. Certain drugs will remain in the body for longer periods of time than other types of drugs. Here is a list of some commonly tested drugs and how long they are detectible in urine:

Alcohol- Less than 1 day
Amphetamines- From 1 to 3 days
Barbiturates- Short acting are up to 1 day, long acting are between 2-3 weeks
Cocaine- Up to 2-4 days
Methadone- Up to 3-5 days
Marijuana- A single use can last from 3-5 days, chronic use can last up to 29 days.
Opioids- Up to 3-4 days
PCP- 2-4 days