FDA approves Tysabri label change for JCV testing: http://finance.yahoo.com/news/FDA-Updates-TYSABRI-bw-1015838179.html?x=0 Notes: • No specific testing interval is cited in BIIB’s PR. • Approximately 55% of MS patients on all drugs are JCV positive. • The FDA has sanctioned DGX to conduct the JCV testing; it’s unclear to me whether other labs can do the testing in accordance with the FDA label.