The US Food and Drug Administration announced its decision to allow XDx Inc. to sell a test, called AlloMap, which is intended to aid in the identification of heart transplant recipients who have a law risk of rejection of the new organ.

The test measures genetic information contained in a patient’s white blood cells, which are cells that normally help defend the body against viruses, bacteria, or other harmful material. The cells can also attack the new organ as a foreign entity. After a patient’s blood sample is tested in the lab, the results provide information on the risk that a heart transplant patient will reject the new organ.

AlloMap is an example on how the science of genetics is changing the practice of medicine, according to the Food and Drug Administration. The test will save the transplant patients from biopsies to check for sign of rejection and it represents an alternative non-invasive method to identify those patients who are more likely to experience postoperative heart transplant rejection.

Dr. James Yee, chief medical officer of XDx, Inc., the company located in Brisbane, Calif., said the test is “non-invasive” and it requires only a blood sample. The test may prove effective in cases of “silent rejection,” when there are no evident symptoms that the body will reject the organ.

According to the FDA, AlloMap gene expression test is the third in vitro diagnostic multivariate index assay (IVDMIA) approved by the FDA.

About 2,600 heart transplants are performed in the United States each year.