CPT® Code 80337

A laboratory test identified by CPT® Code 80337 is utilized to measure the levels of tricyclic and other cyclic antidepressants in biological samples such as urine, serum, or plasma. Tricyclic antidepressants (TCAs) and tetracyclic antidepressants (TeCAs) are classes of medications that primarily function by increasing the concentrations of neurotransmitters in the brain, specifically norepinephrine and serotonin, while simultaneously blocking the action of acetylcholine. These medications are commonly prescribed for a variety of conditions, including depression, anxiety disorders, fibromyalgia, chronic pain syndromes, and even bedwetting in children. Examples of tricyclic antidepressants include clomipramine (Anafranil), amitriptyline (Elavil), desipramine (Norpramin), nortriptyline (Pamelor), doxepin (Sinequan), and trimipramine (Surmontil). Tetracyclic antidepressants, which are also included in this testing, consist of amoxapine (Asendin), loxapine (Loxapac, Loxitan), mirtazapine (Remeron, Avinza), and maprotiline (Ludiomil). The testing process involves obtaining a blood sample through a venipuncture, which is a separately reportable procedure, or a urine sample via random void or catheterization. The analysis of urine, serum, or plasma for TCAs is conducted using quantitative liquid chromatography-tandem mass spectrometry, while the TeCA loxapine is assessed using high-performance liquid chromatography. Additionally, amoxapine is tested using quantitative high-performance liquid chromatography, and maprotiline is evaluated through quantitative gas chromatography. Mirtazapine levels are determined using quantitative gas chromatography or gas chromatography-mass spectrometry. This code is specifically designated for cases where six or more cyclic antidepressants are being evaluated, distinguishing it from codes 80335 and 80336, which are used for testing one to two and three to five compounds, respectively.