Supplementing Surveillance with Hepatitis C Testing Data

BACKGROUND: Long-established hepatitis C virus (HCV) infection surveillance using case-notification methods is fraught with challenges: the lack of a laboratory indicator of acute infection; the large volume of laboratory reports of infection that require review; the lack of symptoms among most chronic cases that dampens healthcare seeking behavior; and the lack of even minimal surveillance resources.  A new, public-private partnership between Quest Diagnostics and CDC can yield basic, state-specific information on volume and rates of positivity for HCV tests, an important supplement to traditional case-based surveillance.   Our objective was to examine state-level HCV testing data and determine whether any changes in the percentage tested and positivity rates occurred before and after publication of CDC screening guidelines for ‘baby boomers’.

METHODS: We analyzed 1,976,304 anonymous HCV antibody tests performed in the United States by Quest Diagnostics between March 2012 and June 2013.  We describe HCV antibody testing and seroprevalence by state and among persons born during 1945-1965 (‘the cohort’) before (6  months, March through August 2012) and after (10 months, September 2012 through June 2013) CDC recommendations for universal screening of that birth cohort. No statistical testing was conducted.

RESULTS: Overall, the number of tests and seropositivity rates did not change substantially before and after the CDC recommendations.  Before the recommendations were published, 745,796 tests/6 months (124,299 tests/month) of which 39,177 (5%) were positive; and after, 1,230, 508 tests/10 months (123,050 tests/month) of which 59,803 (5%) were positive.   The percentage of persons in the cohort tested before and after was also similar (29% before, 32% after). The percentage of persons in the cohort with a positive test was the same (58% before and after).   Most states/jurisdictions (39) had an increase in the percentage of tests that were positive among persons in the1945-1965 birth cohort after the guidelines, 14 had a decrease, and 1 had no change. The percentage of persons in the cohort with a positive test varied by state, but the states with highest and lowest percent of persons in the cohort who were positive was consistent: from 4% before, and 3% after in Wyoming to 21% before, and 17% after in the District of Columbia. 

CONCLUSIONS: Although appreciable changes were not observed over time in the percentage of tests performed and in rates of HCV seropositivity, there was variation by state. Combined with case-based reports and other sources of data, clinical testing data can contribute to a description of the local hepatitis C epidemiologic profile.