1. HIV/AIDS Division, San Francisco General Hospital, University of California San Francisco, San Francisco, California.
2. Department of Emergency Medicine, San Francisco General Hospital, University of California San Francisco, San Francisco, California.
3. Department of Internal Medicine, University of California San Francisco, San Francisco, California.
4. Department of Laboratory Medicine, University of California San Francisco, San Francisco, California.
5. HIV Prevention Section, San Francisco Department of Public Health, San Francisco, California.