In September 1984, the TSS began a nine month planning phase during which the protocols and data systems for the prospective study were developed. Subjects were entered in July 1985 through June 1989. Analysis continued through November 1997. There were clinical centers in Los Angeles, San Francisco, New York City, and Miami. The coordinating center was at the University of Southern California. The central laboratories including the immunological standardization laboratory, the immunological reagents laboratory, and the central processing laboratory were located in Los Angeles, with one of the immunology laboratories located in Seattle, Washington at the Puget Sound Blood Center.