CPT® Code 81493

Coronary artery disease, mRNA, gene expression profiling by real-time RT-PCR of 23 genes, utilizing whole peripheral blood, algorithm reported as a risk score

Gene expression profiling is a sophisticated laboratory procedure that analyzes the activity of specific genes in patients who exhibit stable symptoms indicative of obstructive coronary artery disease (CAD). This test aims to generate a risk score that reflects the patient's likelihood of having CAD based on various factors, including age, sex, and the levels of messenger ribonucleic acid (mRNA) from 23 targeted genes. The underlying connection between CAD and atherosclerotic diseases, such as stroke and myocardial infarction, is rooted in systemic inflammation, which involves various immune cells, including monocytes, macrophages, and CD4+ T-cells, as well as the presence of oxidized lipids. This inflammatory response can affect endothelial cells, vascular smooth muscle cells, and other circulating cells. The gene activity, which is the production of mRNA, can increase in response to environmental stimuli, indicating a biological response to inflammation. Elevated levels of the signature genes tested in this procedure are associated with systemic inflammation and immune-mediated diseases, including CAD. To perform this test, a blood sample is collected through a separately reportable venipuncture. The whole blood sample is then subjected to real-time polymerase chain reaction (RT-PCR), a technique that allows for the assessment of gene expression by determining which genes are actively producing mRNA (and thus proteins) and which are not. The results of this analysis are processed using specialized computer software to generate an algorithmic risk score, which provides insights into the presence of inflammation and the potential risk of CAD in the patient.