HIV Management Guide for Clinical Care

HIV Management Guide for Clinical Care

Co-infections

Management > Co-infections > Diagnosis

Diagnosis

Screening for HCV should be performed in people who have associated identifiable risk factors. Those with HCV are often asymptomatic, unless they have developed advanced liver disease. A major barrier to HCV elimination is that a substantial proportion of those who have acquired HCV are unaware of their status and not adequately screened and therefore, treatment is not made available for them. Identifiable risk factors include: PWID or who have ever injected drugs; people who are incarcerated; people with tattoos or body piercings; people who have received a blood transfusion or organ transplant prior to 1990; people who have received blood products or plasma-derived clotting factor treatment products before 1993; children born to mothers with HCV; people with HIV or HBV; sexual partners of those with HCV or individuals at higher risk of sexual transmission including MSM; people with evidence of liver disease; people who have had a needle-stick injury; and migrants from high-prevalence areas (Egypt, Pakistan, Mediterranean and Eastern Europe, Africa and Asia)15.

Recommended standard-of-care screening test includes HCV serology with anti-HCV antibody testing. Anti-HCV antibodies are detectable in whole blood serum or plasma by enzyme immunoassay (EIA) and are a biochemical indicator for exposure to HCV, whether it be a current or past infection. Anti-HCV antibodies will persist even after spontaneous clearance or treatment-induced viral clearance. Thus, if HCV serology is positive, current HCV infection should be confirmed via polymerase chain reaction (PCR) assay for HCV RNA on plasma or whole blood. False-negative assays are uncommon with third-generation EIA, but failure to detect HCV antibodies in people with HIV has been reported16. Patients who are Anti-HCV antibody-negative with evidence of liver disease, such as having an elevated serum transaminase level or a history of high-risk behaviours, should be evaluated for a detectable HCV RNA to exclude occult HCV infection. Patients diagnosed based on an isolated detectable HCV RNA in plasma or whole blood should have repeat testing for confirmation, as the incubation period for HCV infection is between 2 and 26 weeks17. HCV RNA testing should also be performed in seronegative people with possible early HCV infection, as the antibody response may be delayed by several months. The updated international consensus statements now recommend clinicians practice reflex testing, whenever possible, by requesting both anti-HCV antibodies and HCV RNA in the same plasma or whole blood sample, particularly in population groups considered most at-risk. This substantially increases the likelihood of adequately identifying people with active HCV and linking them in with subsequent treatment and follow-up in a timely and appropriate manner15,18.

Eligibility for PBS-subsidised DAA treatment requires documented evidence of chronic HCV infection, which has traditionally been defined as being anti-HCV antibody and HCV RNA positive for a duration longer than 6 months. However, in someone with a detectable HCV RNA on plasma or whole blood, treatment should not be delayed and a clinical assessment of chronicity can be inferred, unless an individual has a known recent exposure or in the absence of acute hepatitis15.

Documentation of HCV genotype is no longer a mandatory PBS criterion before prescribing DAA treatment, as currently available first-line treatments—sofosbuvir plus velpatasvir; glecaprevir plus pibrentasvir; and sofosbuvir plus velpatasvir plus voxilaprevir—are all pan-genotypic treatment regimens (meaning that they have been proven effective against multiple genotypes). There were several genotype-specific treatment regimens previously available, but these are now no longer marketed in Australia and therefore no longer relevant. However, documentation of HCV genotype may be useful in population groups at high risk of reinfection, where genotype switch would help differentiate reinfection from relapse15,18. History of any prior treatment for HCV, including the treatment regimen and duration course; adherence compliance; and response to treatment, should always be documented. These factors will influence future treatment decisions in the setting of reinfection or relapse15.

Annual HCV serological testing is recommended and should be continued for those who test seronegative but have ongoing risk factors for HCV transmission. In those who are seropositive but have undetectable HCV RNA, indicating a past infection, but with ongoing risk factors for HCV transmission, annual HCV RNA testing is recommended3.

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