Fewer blacks than whites receive the blood-clot busting drug tPA because of delays in seeking emergency care and medical conditions, U.S. researchers say. Dr. Amie Hsia of the Stroke Center at Washington Hospital Center and Georgetown University examined 1,044 patients treated for stroke from Feb. 1, 2008, to Jan. 31, 2009, at seven acute-care hospitals in the District of Columbia. Eighty-percent of the patients studied were black and 20 percent were white, but fewer black patients than whites received the drug tPA because of delays in seeking emergency care and the presence of medical conditions that exclude them from receiving the treatment. For tPA to be effective, a patient must be treated within 3 hours of the onset of symptoms and show disabling deficits such as pronounced weakness or severe speech difficulty, the researchers say. The study, published in Stroke: Journal of the American Heart Association, found a vast majority of black patients are ineligible for the treatment once they arrive at the hospital, in large part because of the delay in seeking treatment, and the effects of poorly controlled stroke risk factors such as high blood pressure or a recent stroke that made them unsafe candidates for treatment.