A blood drug test is used to detect the presence of one or more drugs in a person’s bloodstream. In the employment context, blood tests are used to confirm an employer’s suspicion of drug impairment on-the-job.
If you’ve been asked to take a blood drug test, don’t panic – a blood test has a very short detection window for most drugs, so it’s unlikely to show casual drug use off-the-clock.
Still, the prospect of having your blood drawn at the request of your employer can be nerve-wracking. Here’s what you can expect from your upcoming blood test.
Before the Test
If you have ever had blood drawn for medical testing, you might be wondering if you need to fast ahead of your test. The answer is no – you do not need to fast before drug testing through bloodwork. You should still drink plenty of water beforehand. Drinking water will make for a smoother draw.
Be sure to advise the medical professional who is giving you the test if you have taken any drugs in the past few days. Don’t leave anything out – even over-the-counter drugs, medicines and supplements can show up on your test result. You want to minimize the chance of a false positive.
During the Test
Generally, the doctor or nurse administering the test will collect a blood sample in one of three ways:
- Using a needle to draw blood from a vein in your arm
- Using a needle to draw blood from the back of your hand
- Piercing the skin on your finger to collect a small droplet of blood (known as the fingerstick or fingerprick method)
It’s unlikely you will get to choose which method you use, unless there is a medical reason not to use a vein in your arm or palm.
If you’re apprehensive about needles, ask if you can listen to music, read a book, or watch a relaxing video on your phone while the blood is drawn. If this is not allowed, close your eyes and try to rest for a moment.
After the Test
Depending on the outcome, you will learn the results of the test between 24 hours and a week. Negative results usually arrive sooner than positive results, since the latter needs to be re-evaluated first.
If the test comes up negative, it’s good news. A negative test result means no traces of drugs were found in your sample. Not all drugs can be detected by drug testing through bloodwork, and if enough time has passed since you used a drug, the test may not pick up on it.
If the test comes up positive, it means traces of one or more drugs were found in your blood sample. This doesn’t necessarily mean you’ve ‘failed’ the test, but it’s not good news. Typically, a second, more precise test is conducted to confirm the result before action is taken.