Skip to main content
Explore URMC

URMC Logo

URMC / Encyclopedia / Content

Clonazepam Level (Blood)

Does this test have other names?

Klonopin blood level

What is this test?

This test measures the amount of clonazepam in your blood.

Clonazepam is a medicine used to treat seizures. It's often prescribed to adults and children who suffer from partial seizures and spasms. It may also be used to treat panic attacks, insomnia, and generalized anxiety. It is a type of medicine called a benzodiazepine.

Why do I need this test?

You may have this test if it's possible you have taken an overdose of clonazepam. The test can also be used to monitor the level of clonazepam in your system throughout treatment.

You may also have this test if you are having side effects from clonazepam. These might be drooling, sleepiness, lack of muscle coordination, difficulty breathing, suicidal thoughts, and drowsiness.

What other tests might I have along with this test?

Your healthcare provider may also order other tests, including:

  • Complete blood count, or CBC

  • Liver function tests

  • 7-aminoclonazepam. This is a substance your body makes from clonazepam.

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 provider.

Results are given in micrograms per milliliter (mcg/mL). Therapeutic medicine levels can range from 0.02 to 0.08 mcg/mL. Any level over 0.08 mcg/mL is considered toxic.

How is this test done?

The test requires a blood sample, which is drawn through a needle from a vein in your arm.

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?

Taking other anti-seizure medicines may affect your results. These include valproate and phenytoin. Both clonazepam and 7-aminoclonazepam break down easily. Your results may not be accurate if the sample is not handled properly.

How do I get ready for this test?

You don't 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.

Medical Reviewers:

  • Greco, Frank, MD
  • Sather, Rita, RN