Gene-based Blood Test Performs As Well As Heart Biopsy
A recent study published online in the New England Journal of Medicine finds that the AlloMap blood test from molecular diagnostics company XDx Inc. works as well as routine biopsies in monitoring heart transplant patients for signs of organ rejection; patients in the study receiving the blood test showed similar rates of rejection and complications as those who got biopsies.
This is great news for heart transplant recipients, who typically get 15 to 20 biopsies in the first six months alone after transplant to monitor for signs of organ rejection. During endomyocardial biopsies, doctors insert a tube into veins in the patient’s neck and heart to collect tiny bits of tissue for testing. Hannah Valantine, MD, senior associate dean and professor of Cardiovascular Medicine, Department of Medicine, Stanford School of Medicine, Stanford, CA, who designed the study, says the biopsies are invasive, uncomfortable and have a small risk of complications and death. The findings are also great news for healthcare in general, as biopsies are expensive: $4,000--or $1,000 more than the AlloMap test, Dr. Valantine says. This is not to mention the positive public relations such results bring to the clinical laboratory diagnostics industry.
The study aimed to determine if it is safe to reduce the number of biopsies by using the AlloMap blood test, which determines if specific genes associated with rejection are turned on or expressed. A team compared the results of 600 patients who were randomly assigned to have a biopsy or an echocardiogram and the test. Dr. Valantine and colleagues presented the findings at the International Society for Heart & Lung Transplantation annual meeting in Chicago (April 21-24). Researchers are also doing a cost analysis comparing the two procedures, but those results are not yet available.
The blood test, approved by the FDA in August 2008 for heart transplant patients, is offered at 65 transplant centers in the U.S.