**6. Screening and diagnosis**

Since many infected people are unknown to health care systems due to the asymptomatic nature of the disease, the management of HCV infection should focus not only on therapy but also on the screening of carrier individuals in order to prevent transmission [36]. In the case of a newly acquired infection, the diagnosis of CHC can be made 4–6 months after viral infection [30]. The HCV serologic testing should be offered to individuals who are part of a population with high HCV seroprevalence or who have a history of HCV risk exposure/ behavior. It is also important to consider the possibility of infection with other blood-borne viruses in subjects with HCV, and to offer screening for tuberculosis, hepatitis B virus, and HIV, especially in some groups at risk, such as prisoners and people who inject drugs [18,26]. The current diagnostic techniques for HCV infection are based on a range of tests, including the detection of anti-HCV by enzyme immunoassay in the majority of patients. The test for HCV-RNA by real time polymerase chain reaction is considered the best technique to confirm the presence of viremia and represent the gold standard in HCV diagnosis [lower limit of detection <15 international units (IU)/mL] playing a crucial role in patient management and for choosing the best therapeutic regimen [30,31].

Following spontaneous or treatment-induced viral clearance, anti-HCV antibodies persist in the absence of HCV RNA but might decline and finally disappear in some individuals [37,38]. Additional tests include HCV genotype and subtype determination and host genetics. The improved safety and efficacy of the new DAAs across genotypes could allow a simplified approach to pretreatment screening, without requiring further baseline tests [39].
