In 2000, primary care physicians, surgeons, and other medical specialists began receiving notification from hospital blood banks that a patient they had previously treated or were currently treating may have been exposed to hepatitis C virus (HCV) as a result of blood transfusion. This United States Public Health Service (USPHS)-mandated notification, developed in conjunction with the Food and Drug Administration (FDA), came as a surprise to practitioners, who were faced with the task of locating patients, informing them about the possible exposure, providing appropriate testing and counseling, and possibly evaluating or treating those who were found to be HCV positive, in a process referred to as "lookback."
Lookback encompasses the activities associated with tracing and notifying patients who may have received blood or blood components infected with transfusion-transmissible pathogens (TTP) from a previously infectious disease test-negative, but now positive, donor. Lookback is required for other TTPs such as HIV, but hepatitis C was unique because of the Federal government's highly prescriptive requirements for patient notification, which involved community physicians who cared for or were caring for these patients.
Recognizing that involvement in an HCV lookback process is an infrequent and possibly new experience for many practitioners, the purpose of this discussion is to review the rationale for HCV lookback, define lookback, outline regulatory expectations, and provide physicians with resources that can make the patient notification process less onerous.
GOVERNMENT RESPONSE TO THE HCV EPIDEMIC AND THE HISTORY OF HCV LOOKBACK
It is estimated that up to four million Americans are infected with HCV . The majority of these individuals have been exposed to the virus through the sharing of needles used in injection drug use, and a smaller percentage through sexual contact, perinatally, or occupationally. Approximately one-third of infected people do not identifiably fall into these risk categories, but have a history of behavior, such as multiple sex partners, that places them at higher risk [2,3]. (See "Epidemiology and transmission of hepatitis C virus infection".)
Transfusion transmission once accounted for 0.5 to 10 percent of HCV infections, but due to the use of increasingly sensitive blood donor screening assays, including nucleic acid testing (NAT), the HCV transfusion transmission risk is now about 1 per 2 million units. However, concerns remain within the FDA and the US Public Health Service that there is a population of individuals who may have been exposed to HCV through transfusions in the past.