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Tricyclic Antidepressant Screen

Does this test have other names?

Tricyclic antidepressant (TCA) testing

What is this test?

This test is used to check a sample of blood or urine for tricyclic antidepressants (TCAs). Healthcare providers prescribe these medicines for depression and a number of other problems. These include anxiety, headaches, and nerve-related pain.

These medicines can be helpful in normal doses. But taking too much can be fatal. These medicines are often the cause of death in prescription-medicine overdoses in the U.S. 

Why do I need this test?

You may need this test to help your healthcare provider prescribe the proper dose of a TCA. Healthcare providers may also do this test if you have symptoms that may point to taking too much of one of these medicines.

Symptoms of overdose include:

  • Sedation

  • Trouble thinking

  • Confusion

  • Hallucinations

  • Serious changes in heart rhythm

  • Low blood pressure

  • Seizures

  • Body temperature that is too high (hyperthermia)

  • Dry mouth

  • Dilated pupils

What other tests might I have along with this test?

If your healthcare provider suspects that you have taken too much of one of these medicines, an electrocardiogram is often done to check your heart's rhythm. Your provider may also order other blood tests. These include a complete blood count (CBC), creatinine, electrolytes, and blood sugar. Your provider will also check for other substances that are commonly taken along with a TCA overdose. 

What do my test results mean?

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.

Depending on the tricyclic antidepressant medicine you are taking, the level for treatment will vary.

How is this test done?

The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand. Or it is done with a urine sample, which is usually provided by urinating into a cup. The result of a urine test for TCAs will be reported only as negative or positive.

Does this test pose any risks?

Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore. 

What might affect my test results?

Some other medicines can interfere with this test, causing a false-positive for TCAs. These include carbamazepine, quetiapine, diphenhydramine, and cyclobenzaprine.

How do I get ready for this test?

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 illegal drugs you may use.  

Online Medical Reviewer: Chad Haldeman-Englert MD
Online Medical Reviewer: Raymond Turley Jr PA-C
Online Medical Reviewer: Tara Novick BSN MSN
Date Last Reviewed: 9/1/2022
© 2000-2024 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.