A new blood test may help clinicians identify a patient's risk of rejecting a transplanted heart before allograft rejection can be detected histologically, according to analyses presented at the recent International Society for Heart and Lung Transplantation meeting in Philadelphia, Pa.

The AlloMap test measures the activity of 20 genes involved in transplant rejection and calculates a score that indicates the patient's risk of rejecting a transplanted organ. Research has shown that results correlate highly with those of invasive endomyocardial biopsy. Data for the analyses were derived from the Cardiac Allograft Rejection Gene Expression Observational (CARGO) study database, which covered more than 600 transplant recipients at eight U.S. medical centers.

Developers of the test, XDx, Inc., a biotechnology firm in South San Francisco, Calif., hope it can be used to reduce the need for endomyocardial biopsies, thus reducing the infection risk for transplant recipients. Identifying a patient's risk of organ rejection would also allow clinicians to tailor immunosuppressive therapy to the lowest effective level.