effrey L. Carson, MD, began his mission to examine the efficacy of blood transfusions after a patient declined a transfusion based on religious beliefs. The experience prompted him to research the health outcomes of patients who purposely abstain from the treatment, which in turn led him to study when it is medically necessary to initiate a transfusion. Transfusions are a common medical procedure to supplement blood or parts of blood lost due to disease, injury, or surgery. According to the Centers for Disease Control and Prevention, an estimated five million people receive transfusions in the United States each year. For more than two decades, Dr. Carson, the Richard C. Reynolds Professor of Medicine at Robert Wood Johnson Medical School and provost at Rutgers Biomedical Health Sciences in New Brunswick, has researched blood transfusion strategies. Dr. Carson became a champion of the movement to use the evidence showing it is safe to use less blood in transfusions. The numerous trials he has directed and his reviews of relevant literature provided the foundation for guidelines issued by the AABB (formally known as the American Association of Blood Banks) that endorse a conservative approach when initiating blood transfusions for most patients. Dr. Carson’s work focuses on transfusions to correct low levels of hemoglobin, the protein that utilizes red blood cells to carry oxygen throughout the body. Through analysis of multiple studies, he found that a restrictive transfusion threshold—meaning that patients receive a transfusion only when their hemoglobin concentration is lower than 7 to 8 grams per deciliter (g/dL) rather than the more liberal threshold of 10 g/dL—is safe for most patients. His work led to the creation of national guidelines in 2012 that recommended a restrictive transfusion strategy for most patients. Most recently, Dr. Carson led an international team of scientists and physicians in comprehensive research examining more than 60 years of data on red blood cell transfusions and 31 clinical trials that evaluated outcomes for more than 12,500 individuals who received transfusions at the restrictive rather than liberal threshold. The study provided evidence needed to update the original transfusion guidelines, prompting the AABB to recommend that most patients who need blood transfusions—including those who are critically ill—need not be given blood before their hemoglobin drops to a lower level than the practice followed traditionally. The guidelines were published online in October by the Journal of the American Medical Association (JAMA). “Clinically, the results of our work show that no harm will come from waiting to transfuse a patient until the hemoglo30 Robert Wood Johnson I MEDICINE J bin level reaches a lower point,” says Dr. Carson, first author of the JAMA paper and co-chair of the AABB guideline panel. “The restrictive approach is associated with reductions in blood use, blood conservation, and lower expenses.” The recommendations to utilize the lower transfusion threshold—7 to 8 g/dL for most patients—apply to surgery patients, and others whose blood counts reach low enough levels to threaten their lives. The AABB said that based on the new evidence, transfusions at a lower level are also recommended for critical care patients, as well as those undergoing orthopedic and cardiac surgery, and those with preexisting cardiovascular disease. But according to Dr. Carson, further clinical trials are needed to determine whether heart attack patients who also have anemia, as well as those with a bone marrow disorder, benefit from a transfusion at higher hemoglobin levels. His knowledge is based on preliminary evidence from several small studies, including a pilot study that he oversaw, which found that patients who have had a heart attack and have anemia, which restricts the body’s ability to carry oxygen, may have an increased risk of mortality with a restrictive transfusion approach. Even before the study in JAMA was published, Dr. Carson began to establish evidence that can be used to set transfusion standards for this population of patients, to improve their survival rates and reduce the risk of recurrence. A further study has generous backing from the National Institutes of Health (NIH). “We are about to embark on a large international clinical trial supported by the NIH that will provide the evidence needed to determine the best course of action for patients who have had a heart attack,” says Dr. Carson. “It’s important to establish evidence-based standards to improve patient safety and outcomes.” Awarded more than $16.1 million by the NIH’s National Heart, Lung, and Blood Institute in September, Dr. Carson will oversee the Myocardial Ischemia and Transfusion (MINT) clinical trial, which will be conducted in up to 80 centers in the United States and Canada. The trial will include 3,500 patients, who will be randomly allocated to be treated according to either a liberal or a restrictive transfusion strategy. The study will evaluate the differences in outcomes between the two transfusion approaches. Patients who qualify for the trial will be recommended by participating physicians. Dr. Carson, who is the study chair and principal investigator of the clinical coordinating center, will work with Maria Mori Brooks, PhD, professor and vice chair of education, Department of Epidemiology, codirector, Epidemiology