Corus CAD Explained

A genetic test, as opposed to a physical measurement, Corus CAD looks for evidence of narrowing or blockage in the coronary arteries at the molecular level. Blood samples are screened for the activity of 23 genes that exhibit changes when there's an obstruction in the arteries. It's gender specific, taking into account differences in how men and women respond to obstructive coronary artery disease.

How it's done: A blood sample is sent to the specialized laboratory of CardioDX, the company that makes Corus CAD. Results are available within 72 hours.

Who should get it: People experiencing chest pain, tightness, or pressure that could suggest a narrowing coronary artery. (One telltale sign that chest pain might indicate arterial blockage is if symptoms increase with exercise or exertion.) Shortness of breath or unexplained fatigue are other signs. You aren't a candidate for Corus CAD if you've had a previous heart attack or artery-opening procedure. Corus CAD also isn't recommended if you're diabetic, on steroids, having chemo, or taking immunosuppressive drugs.

How it's different: Corus CAD can detect multivessel coronary artery disease in people who are having unexplained chest pain but would otherwise be considered at low risk. Corus CAD is considered an alternative to myocardial perfusion image testing (MPI), which uses a radioactive agent to test for blockages in cardiac blood flow, followed by angiogram. For example, the New England Journal of Medicine recently reported that of 400 patients who underwent invasive angiography, 62 percent turned out to have no obstructive blockage. Corus CAD potentially could be used to more effectively sort out candidates prior to performing invasive angiograms.

Cost: Approximately $1,200. Some insurers cover Corus CAD, but most don't. Check with your insurance company first. CardioDX offers a financial assistance program to help those who can't afford the test.