Accuracy and Reliability of Drug Tests

Having reliable test results for at-home drug tests has to do with quite a few factors: type of test, avoiding human error, and understanding results. Drug screening includes options such as: urine test, hair and saliva drug tests, and blood testing. Accuracy and reliability are important for results you can trust. Using the correct test and following the instruction procedure closely will help you get the best results and read them correctly, whether a negative or positive result.

Blood tests are the most accurate drug tests but are also the most expensive option. Another challenge with blood tests is that drugs do not stay in the blood long; for example, marijuana only stays in the blood for a few hours after a single use and stays for 24 hours for chronic users. Other types of test options include urine, hair, saliva, and sweat tests. Hair is especially useful for seeing drug use pattern over a longer period of time (2-4 months).  However, a false positive is a possibility with hair tests because even walking in a room where marijuana smoke is present can result in a positive test result. Saliva tests are nonintrusive, yet they do not have any nationally accepted cutoff levels. Sweat patch tests have a high likelihood of false positives, since the skin can easily be contaminated.

However, urine tests, such as the EDOAP-754, are the most common option because they are inexpensive, less invasive, and have a longer detection time than some other drug test options.