URL of this page: https://medlineplus.gov/lab-tests/tricyclic-antidepressant-tca-screen/

Tricyclic Antidepressant (TCA) Screen

What is a tricyclic antidepressant (TCA) screen?

This test checks for the amount or the presence of tricyclic antidepressants (TCA) in blood or urine. TCAs are a type of antidepressant. Antidepressants are medicines that treat depression, a serious illness that can affect how you think, feel, and behave. There are several types of antidepressants. They each work in slightly different ways.

TCAs were one of the first types of antidepressants developed. They can be effective, but they tend to cause more side effects than newer types of antidepressants. But since it's common for antidepressants to become less effective or ineffective over time, TCAs can be a good option to treat depression when other antidepressants have failed.

Commonly prescribed TCAs include:

  • Doxepin
  • Nortriptyline
  • Amitriptyline
  • Imipramine
  • Desipramine

TCAs have to be carefully dosed. It can be hard to find a dose that is effective without being dangerous. In fact, TCAs are the cause of many prescription drug overdose deaths in the United States.

Other names: TCA test, TCA screen

What is it used for?

A TCA screen is used to:

  • Help your health care provider prescribe the right dose of a TCA
  • Find out if you are misusing TCA (taking it without a prescription or taking more than the prescribed dose). The test may be included as part of a drug (toxicology) screen, a test that checks for the presence of several different prescription and illegal drugs.
  • Diagnose a TCA overdose. Prompt treatment of an overdose can be lifesaving.

Why do I need a TCA screen?

You may need this test if you have been prescribed a TCA to make sure you are getting a dose that is safe and effective. You may also need this test if you have symptoms of a TCA overdose.

These include:

What happens during a TCA screen?

A TCA screen can be done as a blood test or a urine test.

During a TCA blood test, a health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

For a TCA urine test, you will need to provide a sample of urine into a sterile cup. Your provider will give more information on how to collect your sample.

Will I need to do anything to prepare for the test?

You don't need any special preparations for a TCA screen.

Are there any risks to the test?

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

There is no risk to having a urine test.

What do the results mean?

Your blood test results will show the levels of TCA in your bloodstream. Depending on the levels and on which TCA you are taking, your provider may adjust your dosage.

There are two types of urine test results. One type will show whether TCA was found, but not how much. The other type shows the levels of TCA.

If blood or urine test results show you have dangerously high levels of TCA, you will be treated immediately.

If you have questions about your results, talk to your health care provider.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about a TCA screen?

TCAs are most often prescribed by a mental health professional, a specialist in diagnosing and treating mental health problems, such as depression. There are many types of mental health professionals. Some types, usually medical doctors, are allowed to prescribe medicines including TCAs. Other mental health professionals work with providers who are able to write prescriptions. The most common types of mental health professionals include:

  • Psychiatrist, a medical doctor who specializes in mental health. Psychiatrists diagnose and treat mental health disorders. They can prescribe medicine.
  • Psychologist, a professional trained in psychology. Psychologists generally have doctoral degrees, such as a Ph.D. (Doctor of Philosophy) or a Psy.D. (Doctor of Psychology). But they do not have medical degrees. Psychologists diagnose and treat mental health disorders. They may offer one-on-one counseling and/or group therapy sessions. They can prescribe medicine if they have a special license. If not, they may work with providers who are able to.
  • Licensed clinical social worker (L.C.S.W.) has a master's degree in social work with training in mental health. Some have additional degrees and training. L.C.S.W.s diagnose and provide counseling for a variety of mental health problems. They can't prescribe medicine but can work with providers who are able to.
  • Licensed professional counselor (L.P.C.). Most L.P.C.s have a master's degree. But training requirements vary by state. L.P.C.s diagnose and provide counseling for a variety of mental health problems. They can't prescribe medicine but can work with providers who are able to. L.C.S.W.s and L.P.C.s may be known by other names, including therapist, clinician, or counselor.
  • Advanced practice registered nurses (APRNs) are specially trained nurses who have a master’s or doctoral degree in psychiatric nursing. They assess, diagnose, and treat a variety of mental health disorders. Some ARPNs can prescribe medicines.

If you have depression, it's important to get treatment. If you don't know which type of mental health provider you should see, talk to your primary care provider.


  1. American Psychiatric Nurses Association [Internet]. Falls Church (VA): American Psychiatric Nurses Association; Psychiatric Mental Health Nurses; [cited 2021 Aug 2]; [about 3 screens]. Available from: https://www.apna.org/i4a/pages/index.cfm?pageid=3292 
  2. American Psychiatric Association [Internet]. Washington D.C.: American Psychiatric Association; c2020. What Is Depression?; [cited 2020 Dec 7]; [about 3 screens]. Available from: https://www.psychiatry.org/patients-families/depression/what-is-depression
  3. Familydoctor.org [Internet]. Leawood (KS): American Academy of Family Physicians; c2020. Types of Antidepressants; [updated 2020 May 26; cited 2020 Dec 7]; [about 4 screens]. Available from: https://familydoctor.org/types-of-antidepressants
  4. Johns Hopkins Medicine [Internet]. Baltimore: The Johns Hopkins University; c2020. Health: Why Aren't My Antidepressants Working; [cited 2020 Dec 7]; [about 3 screens]. Available from: https://www.hopkinsmedicine.org/health/wellness-and-prevention/why-arent-my-antidepressants-working
  5. Lab Tests Online [Internet]. Washington D.C.: American Association for Clinical Chemistry; c2001–2020. Urinalysis; [updated 2020 Aug 12; cited 2020 Dec 7]; [about 2 screens]. Available from: https://labtestsonline.org/tests/urinalysis
  6. Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998–2020. Antidepressants: Selecting one that's right for you; 2019 Dec 31 [cited 2020 Dec 7]; [about 3 screens]. Available from: https://www.mayoclinic.org/diseases-conditions/depression/in-depth/antidepressants/art-20046273
  7. Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998–2020. Mental health providers: Tips on finding one; 2017 May 16 [cited 2020 Dec 7]; [about 3 screens]. Available from: https://www.mayoclinic.org/diseases-conditions/mental-illness/in-depth/mental-health-providers/art-20045530
  8. Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998–2020. Tricyclic antidepressants and tetracyclic antidepressants; 2019 Oct 8 [cited 2020 Dec 7]; [about 3 screens]. Available from: https://www.mayoclinic.org/diseases-conditions/depression/in-depth/antidepressants/art-20046983
  9. National Heart, Lung, and Blood Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; Blood Tests; [cited 2020 Dec 7]; [about 3 screens]. Available from: https://www.nhlbi.nih.gov/health-topics/blood-tests
  10. Preskorn SH. Tricyclic antidepressants: the whys and hows of therapeutic drug monitoring. J Clin Psychiatry [Internet]. Jul 1989 [cited 2020 Dec 7]; 50 Suppl:34-42; discussion 43-6. Available from: https://pubmed.ncbi.nlm.nih.gov/2661550
  11. Request A Test [Internet]. Brecksville (OH): Request A Test; c2020. Tricyclic TCA Antidepressants Test; [cited 2020 Dec 7]; [about 3 screens]. Available from: https://requestatest.com/Tricyclic-TCA-Antidepressants-Screen-test
  12. UCSF Medical Center [Internet]. San Francisco (CA): The Regents of the University of California; c2002-2019. Toxicology Screen; [cited 2020 Dec 17]; [about 3 screens]. Available from: https://www.ucsfbenioffchildrens.org/tests/003578.html
  13. University of Rochester Medical Center [Internet]. Rochester (NY): University of Rochester Medical Center; c2020. Health Encyclopedia: Tricyclic Antidepressant Screen; [cited 2020 Dec 7]; [about 2 screens]. Available from: https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=tricyclic_antidepressant
  14. Utah Poison Control Center [Internet]. Salt Lake City: University of Utah Health; c2020. Toxicology Today: Tricyclic Antidepressant (TCA) Screening; [cited 2020 Dec 7]; [about 4 screens]. Available from: https://poisoncontrol.utah.edu/newsletters/pdfs/toxicology-today-archive/Vol15_Iss3.pdf
  15. UW Health [Internet]. Madison (WI): University of Wisconsin Hospitals and Clinics Authority; c2020. Healthwise Knowledgebase: Antidepressants; [cited 2020 Dec 7; [about 3 screens]. Available from: https://patient.uwhealth.org/healthwise/article/pl1023

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.