Hepatitis C Virus Infection Testing

According to the Centers for Disease Control and Prevention (CDC), there are an estimated 3.2 million people in the United States living with hepatitis C virus (HCV) infection and new infections continue to occur. Once infected with HCV, approximately 80% of persons remain infected and are at risk for morbidity and mortality later in life.

Current CDC laboratory testing and reporting guidelines of antibody to HCV make no distinction between past infection that has resolved and current infection requiring care and evaluation for treatment. A test for HCV RNA is required to identify current infection.

The May 7, 2013, CDC Morbidity and Mortality Weekly Report (Vol. 62), Vital Signs: Evaluation of Hepatitis C Virus Infection Testing and Reporting—Eight US Sites, 2005-2011, reports on data from HCV infection surveillance programs that can be used to determine the proportion of persons who might need additional testing to discriminate previous resolved infection from current infection.

The surveillance programs for HCV infection were in place at 8 sites in the United States by 2011 (Colorado, Connecticut, Minnesota, New Mexico, New York City, New York State, Oregon, and San Francisco). For all 8 sites, clinical laboratories reported only positive test results of HCV infection from HCV antibody testing or from HCV RNA testing; there were no health department requirements to report negative results.

For the current analysis, persons reported with a positive result from an HCV antibody test only were compared with persons reported with a positive result for HCV RNA and examined by birth cohort (1945-1965 compared with all other years), surveillance site, and number of reported deaths. In addition, annual rates of persons newly reported with HCV infection in 2001 were calculated for each site.

During 2005 to 2011, a total of 217,755 persons among all 8 sites were newly reported with a positive test result for HCV infection. Of those, 49.2% (n=107,209) were HCV antibody positive only and 50.8% (n=110,546) were HCV RNA positive. Birth year was more likely to be from 1945 to 1965 in both groups. Persons born from 1945 to 1965 accounted for 58.5% of those who were HCV antibody positive only and 67.2% of those who were HCV RNA positive.

Among the sites reporting deaths, 6734 (3.4%) of persons newly reported with HCV infection were known to have died. The highest percentage of deaths occurred among persons 50 to 59 years of age (44.8%), and 71.5% of the deaths were among those born during 1945 to 1965, compared with other years. The percentage of deaths reported with HCV antibody positive only (4.6%) was significantly higher than among those reported as HCV RNA positive (2.4%; P<.01).

In 2011, the annual rate of all persons newly reported with HCV infection (both HCV antibody positive only and HCV RNA positive) across all sites was 84.7 per 100,000 population (range: 36.0 in Minnesota to 239.2 in San Francisco).

The report’s authors stated, “Hepatitis C is a commonly reported disease predominantly affecting persons born during 1945 to 1965, with deaths more frequent among persons of relatively young age. The lack of a HCV RNA test for approximately one half of persons newly reported suggests that testing and reporting must improve to detect all persons with current infection.”

In outlining implications for public health, the authors continued, “In an era of continued HCV transmission and expanding options for curative antiviral therapies, surveillance that identifies current HCV infection can help assess the need for services and link persons with infection to appropriate care and treatment.”