Rejection of the donor organ is a frequent and sometimes life-threatening complication of heart transplantation. It is best handled if caught early, and since early rejection is typically asymptomatic, physicians had heretofore been required to perform regular biopsies to screen for rejection of the transplanted heart.

The biopsy is expensive and not without risk however, so scientists have long searched for a non-invasive alternative to diagnose rejection.

That search may have yielded results. In a presentation at last month’s meeting of the International Society for Heart & Lung Transplantation, Michael Pham and colleagues from Stanford University showed that a genetic test reduced the need for biopsies in selected patients.

The gene test is known as Allomap. It is marketed by XDx and has been used on 7,000 transplant recipients so far. It costs about $3,000, or 25-40% less than the biopsy.

The study by Pham’s team included 602 transplant recipients. It showed that Allomap was as effective as routine biopsies in preventing serious episodes of transplant rejection like heart failure, the need for a re-transplant or death.

The study was limited to patients who were at low risk for rejection and had undergone the procedure at least 6 months prior to enrollment. Nineteen months after randomization, 14.5% of patients that were followed with the genetic test and 15.3% of those followed with routine biopsies suffered a major complication.

“You’re not going to harm patients by reducing the number of biopsies,” Pham told the Wall Street Journal.

Pham noted that his team’s findings could not be extrapolated to patients that had received a transplant within the last 6 months or to those at high risk for rejection.

The study appears in the New England Journal of Medicine.