How Accurate Are Drug Tests?

Drug tests are relatively common in the U.S. Most people have been tested at one time or another when applying for a job. Addiction treatment centers also administer drug tests to patients. But how accurate are these tests? Are they reliable?

The short answer: it depends. Some types of drug testing are highly accurate, while others are much more error-prone. There are five main types of drug test:

  • Urine tests
  • Blood tests
  • Saliva tests
  • Sweat tests
  • Hair tests

Most of these testing methods are, on the whole, accurate. In general, hair tests and blood tests are the most accurate testing methods. However, they tend to be relatively expensive, so many employers and rehab facilities do not use them. Urine tests are more commonly administered, but they tend to be a little more error-prone.

One frequently asked question is whether it’s possible to “cheat” on a drug test. Again, the answer is that it depends. Some testing methods are easier to fool than others. Urine testing, in particular, is vulnerable to cheaters. It’s much harder – if not impossible – to cheat on a blood test or a hair test.

Keep reading to learn more about each type of drug testing and its accuracy.

 

More Information on the Different Types of Drug Tests

When most people hear the words “drug test,” they think of a urine test. Urine testing is the most common form of drug testing because it’s quick and inexpensive. It’s also accurate – most of the time. Some people have found ways to tamper with urine testing, such as drinking lots of water ahead of time, mixing their urine with other additives, or even using someone else’s urine.

Hair testing is less common than urine testing. It’s more expensive and it takes longer, because the sample of hair must be sent to a lab for analysis. However, a hair test is hard to fool, because drug metabolites get locked in the hair strands permanently. Certain shampoos claim to be able to get rid of the metabolites, but there’s no evidence they work.

Blood tests and saliva tests also tend to be accurate. In fact, blood testing is the most accurate form of testing available right now. However, these tests only work within a short window of time. Most of the time, these tests are only accurate if a person has used drugs within the last few days.

A sweat test involves wearing a patch on the skin. While these tests can pick up traces of drugs in a person’s sweat, they’re also prone to giving false positives. Dirt and other substances can render a sweat test inaccurate, so these tests aren’t commonly used.