CPT® Code 80166

Deleted

The CPT® Code 80166 refers to a laboratory test specifically designed to measure the levels of doxepin in the blood. Doxepin, which is also known by its brand name Sinequan, is classified as a tricyclic antidepressant. It is primarily utilized in the treatment of various mental health conditions, including depression and anxiety disorders. The test is crucial for monitoring the therapeutic levels of doxepin, which are defined as being between 100 to 300 ng/ml. Levels exceeding 500 ng/ml are considered toxic and may lead to adverse effects. Symptoms associated with doxepin toxicity can manifest as anticholinergic effects, which include flushing, dry skin, dry mucous membranes, urinary retention, and an increased heart rate, known as tachycardia. To accurately assess doxepin levels, a blood sample is collected through a procedure known as venipuncture, which is separately reportable. It is important that the blood draw occurs prior to the administration of the drug to ensure that the measurement reflects the trough level of doxepin. The analysis of the serum or plasma is conducted using a sophisticated technique called quantitative liquid chromatography-tandem mass spectrometry, which allows for precise quantification of the drug in the sample.