However, other scientific studies question the effectiveness of leukoreduction. A March 2007 study by researchers at University of South Alabama Medical Center found no reduction of mortality or length of hospital stay in 439 trauma patients who received leukoreduced transfusions compared to 240 patients who did not. University of Washington researchers reported in October 2006 that a study of 286 transfused injury patients showed no reduction in mortality or length of stay, although a 16% reduction in rate of infection was shown with marginal statistical significance.