292. Describe the four stages of tuberculosis infection April 9th, 2008 by reuben in TB Back Top Tags: card 291. How long after initiating multidrug antituberculous therapy must pt be isolated, if AFB negative and no extensive disease? / How long if AFB positive or extensive disease? 293. What is the rate of development of clinically active TB in healthy PPD converters and HIV patients? / TB RFs Leave a Reply Cancel reply Please post any discussion to the emupdates Reddit page.