Rejection hurts, but organ transplant rejection hurts worse, and CareDx wants to help. The company makes tests that monitor cellular rejection in heart and kidney transplant patients. Its FDA-approved AlloMap test measures gene expression in patients' blood samples to determine if a transplanted heart has been accepted. The company believes its tests will help reduce costs by decreasing the number of biopsies and drug therapies often used in evaluating transplants in patients. CareDx is also working on the development of AlloMap for kidney transplant patients, and it has other molecular (gene-based) diagnostic research programs in areas such as immunology. Founded in 1998, the company went public in 2014.