Test Details: This test checks for the amount or the presence of tricyclic antidepressants (TCA). TCAs are a type of antidepressant. Antidepressants are medicines that treat depression, a serious illness that can affect how an individual may think, feel, and behave. A TCA screen is used to prescribe the right dose of a TCA, find out misuse of TCA and diagnose a TCA overdose