Hepatitis C Virus (HCV) Antibody, Total

The Hepatitis C Virus (HCV) Antibody, Total test (anti‑HCV, total; HCV antibody, total) is employed to screen for hepatitis C and to support the initial workup of suspected HCV infection. It aids in the differential diagnosis of hepatitis and documents prior exposure to the virus. Reactive antibody screens require confirmatory HCV RNA testing to verify active infection and to inform clinical staging and treatment planning.

Hepatitis C virus is an RNA virus within the Flaviviridae family with a primary affinity for the liver and the ability to replicate in hematopoietic cells, including neutrophils, monocytes/macrophages, and B lymphocytes. Infection is associated with mixed cryoglobulinemia, Sjögren syndrome, and B‑cell lymphoproliferative disorders. Six genotypes with multiple subtypes have recognized prognostic and therapeutic implications. Transmission is predominantly parenteral, such as through blood transfusion prior to screening, transplantation, nonsterile needles, and tattooing or piercing instruments; sexual and perinatal spread occur less often. Acute HCV infection is frequently silent; only a minority develop symptomatic illness, and jaundice is uncommon. Chronic infection develops in approximately 60%–85% of cases, often with fluctuating aminotransferase values and few symptoms; 20%–30% progress to cirrhosis with attendant risks of hepatic failure and hepatocellular carcinoma. Humoral responses target core (nucleocapsid), envelope (E1–E2), and nonstructural (NS) proteins. Anti‑HCV usually becomes detectable 1–3 months after infection, though seroconversion can be delayed beyond one year, and about 5% of infected individuals never develop detectable antibodies. During acute infection, IgM and IgG to core proteins appear; during latency or reactivation, IgG directed to NS and core antigens predominates. After resolution of infection, antibodies may persist for many years or lifelong at low titers and do not provide protective immunity.