Blood Drug Test Facts

The following blood drug test facts will help you know what you're getting into before you take a blood drug test. They may also help you in the case of a false positive drug test and subsequent court challenge. Here are some things you need to know about blood drug tests. 

  1. Blood drug tests can detect marijuana use for two weeks or more. This is true if you are a frequent marijuana user. Infrequent smokers can test positive for up to three days. 
  2. Blood drug testing is no indicator of current intoxication. Many institutions prefer blood drug tests because the time window between when you last used and the time of the blood test is shorter than that of urine testing. However, you can test positive for days or weeks after smoking marijuana. A blood test can detect methamphetamine use for three days. 
  3. False positive rates vary from laboratory to laboratory. There are many factors that determine false positive rates. Every step in the blood drug test process holds opportunities to create false positives. If you plan to challenge a drug test in court, make sure that you get the drug testing company's false positive rate, historical information about the facility's licensing and whether their license has ever been suspended or revoked. Gather the facts and use them in court. 
  4. You are more likely to have a positive blood drug test in the morning. Your body processes impurities throughout the day. The highest concentrations of drug waste will appear in your blood and urine in the morning. 

Drug testing can be a big deal whether you use illegal drugs or not. Many innocent people have falsely tested positive in blood drug tests. People can and do lose their jobs and get thrown in jail for probation violations. Whatever your situation, hopefully the above blood drug test facts will help you.