Development of Qualitative HCV RNA Testing on Dried Blood Spots as an Adjunct Screening Tool to Identify Active Hepatitis C Infection
Tackling hepatitis C infection has been identified as a strategic priority for Public Health England. Increased awareness, testing and referral for treatment are among the initiatives introduced as part of a public health strategy. The use of rapid tests among persons at increased risk of HCV infection is currently advocated to facilitate enhanced surveillance. Screening with dried blood spots (DBS), using finger-prick capillary blood, combines ease of testing in a community setting with minimum sample requirement and therefore is an ideal tool for those who are difficult to bleed or refuse venepuncture.
Screening for blood borne viruses using DBS was developed in our laboratory to test individuals from high risk populations, including prisoners. Blood spots were eluted using a specific buffer and tested in semi-automated assays for the presence of hepatitis B surface antigen (HBsAg) as well as antibodies against human immunodeficiency virus (HIV) and hepatitis C virus (HCV). In addition, elution of dried blood spots was modified to allow a qualitative detection of HCV RNA using RT-PCR.
Results: The lower limit of detection for HCV RNA in DBS was determined to be 1 x 103IU/mL. Over a six month period from June - November 2013, 5005 individuals were screened for hepatitis C using DBS in an ‘opt-in’ programme. Of those screened, 537 (10.7%) were found to be HCV antibody positive. In addition, screening for hepatitis C RNA on DBS was done in 458 of these HCV-antibody positive individuals, of which 258 had detectable HCV RNA (62.8%), indicating active infection.
Qualitative detection of HCV RNA from dried blood spots is sensitive enough to be used as an additional screening tool in high risk and difficult-to-reach populations. A positive RNA result indicates active infection and enables immediate referral of patients for specialist care, thus avoiding delay and possible loss to follow-up of patients that are consequent on having to obtain a second sample.
S. Wilson, None
H. Osman, None
S. Atabani, None
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