Does this test have other names?
Benzodiazepine drug screen
What is this test?
This is a blood test to screen for a class of drugs called benzodiazepines (ben-ZOH-die-AZ-uh-peens).
Benzodiazepines are central nervous system depressants. They are used to sedate patients,
help them sleep, prevent seizures, ease anxiety, and relax muscle spasms. These drugs
are often informally called tranquilizers, sleeping pills, and muscle relaxants.
Variations in the molecules of different benzodiazepines give them their specific
chemical properties and medical uses.
Examples of common antianxiety medicines, muscle relaxants, and antiseizure medicines
Examples of common sedative-hypnotic medications include:
In addition to medical use, benzodiazepines are sometimes used illegally. Chronic
abuse of benzodiazepines can lead to addiction, and combining these drugs with other
depressants like alcohol can be fatal. Street names for these drugs include "downers,"
"benzos," "nerve pills," "candy," and "tranks."
Why do I need this test?
Even if you have been prescribed these drugs, you may need this test if you are showing
signs of an overdose. Symptoms of overdose include confusion, slurred speech, loss
of muscular coordination, stupor, and unconsciousness. Benzodiazepines can also cause
low blood pressure, slow or shallow breathing, and cardiac arrest.
You may also have this test if a healthcare provider suspects you are abusing the
drugs illegally or without a prescription.
If you appear confused, cannot be roused, have seizures, or lose muscle control, you
may also have this test as part of an overall drug screen to check for other commonly
abused drugs. These screens vary at different hospitals, but often include tests for
cocaine, opioids, amphetamines, barbiturates, benzodiazepines, marijuana or phencyclidine.
If you are conscious, able to talk with healthcare providers, and willing to cooperate,
you can give information that helps providers figure out the right test for your case.
For example, if you are a victim of sexual assault, you may have this test to find
out whether someone slipped a benzodiazepine date rape drug, such as Rohypnol ("roofie"),
into your drink.
You might also be tested if healthcare providers think you have taken benzodiazepines
accidentally or in a suicide attempt.
What other tests might I have along with this test?
If you seem to have an altered mental state, healthcare providers will most likely
give you a glucose test to check your blood sugar. If you are brought to a hospital
showing symptoms of central nervous system depression, such as confusion, slurred
speech, seizure, or coma, you may be tested for a variety of drugs, including benzodiazepines.
A benzodiazepine overdose alone is unlikely to cause coma or severe heart or lung
function problems. If you have those symptoms, a healthcare provider may screen for
other drugs and test for causes of central nervous system depression that aren't drug-related.
In addition to a blood test, a healthcare provider may also order a urine test for
benzodiazepines, or a urine toxicology screen for a variety of substances. Urine tests
are generally less expensive and less invasive than blood tests. But blood tests are
harder for a person to tamper with to hide drug abuse.
Exactly which lab tests you have depends on your physical exam and information about
your condition that you are willing and able to provide.
What do my test results mean?
Many things may affect your lab test results. These include the method each lab uses
to do the test. Even if your test results are different from the normal value, you
may not have a problem. To learn what the results mean for you, talk with your healthcare
The result of a benzodiazepine blood test is either positive or negative. A positive
blood test for benzodiazepines may also be able to measure the amount of drug in the
Different benzodiazepines have different therapeutic doses, ranging from 0.5 to 50
milligrams (mg). Overdoses of 10 of 20 times the prescribed dose of some benzodiazepines
can result in a mild coma, but usually don't cause slow or shallow breathing. Most
But overdoses of fast-acting benzodiazepines like triazolam (Halcion) are more likely
to cause breathing problems and even death.
A medicine called flumazenil (Romazicon) may be used as an antidote to the sedative
effects of benzodiazepines. It shouldn't be used in people who have been taking benzodiazepines
over a long period to control seizures. In such cases, flumazenil could cause potentially
How is this test done?
The test requires a blood sample, which is drawn through a needle from a vein in your
Does this test pose any risks?
Taking a blood sample with a needle carries risks that include bleeding, infection,
bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight
stinging sensation or pain. Afterward, the site may be slightly sore.
What might affect my test results?
Older adults and people with liver disease may not eliminate certain benzodiazepines
as quickly as other people. Their test results may show higher levels from the same
How do I get ready for this test?
You do not need to prepare for this test. But be sure your healthcare provider knows
about all medicines, herbs, vitamins, and supplements you are taking. This includes
medicines that don’t need a prescription and any illicit drugs you may use.