Clinical experience with tissue plasminogen activator stored at -20 degrees C

We developed a new dilution technique that allows tissue plasminogen activator (t-PA) to be stored at -20 degrees C, as opposed to the -70 degrees C recommended by the United States manufacturer (Genentech Inc). Following tests that showed neither loss in activity nor microbiological contamination, we clinically proved the efficacy of t-PA stored at -20 degrees C in 10 cases.