The study was renewed in 1993 in order to develop a protocol and manual of operations for continuation of the study on the long- term follow-up of transfusion-associated non-A,non-B (NANB) hepatitis; to conduct annual National Death Index (NDI) searches for all cohort members who were alive or not located at last follow-up; to obtain and code death certificates for all newly deceased; and to collect and abstract medical records for all hospitalizations that occurred since the last follow-up for newly deceased subjects. The searches were conducted to determine whether a mortality difference between the infected cohort and the controls would develop with longer observation, as was suggested by the continued presence of chronic liver disease. Each surviving member was contacted annually, and medical records for all hospitalizations that occurred since the last follow-up for those subjects who reported liver disease were collected and abstracted. The contacts ensured that any liver disease that may have been missed through enzyme screening, or which may have newly developed, would be identified.